Read this manual before servicing the snowplow.library.westernplows.com/pdfs/21936_121704.pdf · Read this manual before servicing the snowplow. No. 21936 December 17, ... assist

December 17, 2004No. 21936

SNOWPLOWS

MECHANIC'S GUIDEMECHANIC'S GUIDEMECHANIC'S GUIDEMECHANIC'S GUIDEMECHANIC'S GUIDE

SNO SNO SNO SNO SNOWPLWPLWPLWPLWPLOOOOOWSWSWSWSWS

Featuring theISARMATIC® Hydraulic System

CAUTIONRead this manual before servicing the snowplow.

No. 21936 December 17, 2004

3

PREFACETABLE OF CONTENTS

This guide has been prepared toassist the trained mechanic in theservice of WESTERN® snowplows.It also provides safety informationand recommendations. We urge allmechanics to read this manualcarefully before attempting to servicethe WESTERN snowplow equipmentcovered by this guide.

Service of your WESTERNsnowplow equipment is bestperformed by your local WesternProducts outlet. They know yoursnowplow best and are interested inyour complete satisfaction.

Preface .............................................................................................................3ISARMATIC® Hydraulic System ......................................................................6

Product Specifications .............................................................................6Required Tools ..........................................................................................6Hydraulic Hose Routing ...........................................................................7Hydraulic Unit Parts Diagram ..................................................................8Solenoid Cartridge Valve Identification and Location ...........................9

Vehicle Harness and Vehicle Cable Location .............................................10Operating the Snowplow .............................................................................. 11Theory of Operation ......................................................................................13Hydraulic and Electrical Schematics ...........................................................14

Electrical Schematic ...............................................................................15Hydraulic Schematic ...............................................................................17Angle Right ..............................................................................................18Angle Left ................................................................................................20

Raise ........................................................................................................22Lower .......................................................................................................24Hold in Raise Position ............................................................................26Striking An Object While Plowing – Right Cylinder Retracts ..............27

Striking an Object While Plowing – Left Cylinder Retracts .................28Headlamps – Plow Not Connected – Vehicle Only ...............................29High Beam Headlamps With Plow Connected to Vehicle ....................31Low Beam Headlamps With Plow Connected to Vehicle ....................33

Troubleshooting Guide .................................................................................35

No. 21936 December 17, 2004

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WARNING

Vehicle exhaust contains deadlycarbon monoxide (CO) gas.Breathing this gas, even in lowconcentrations, could causedeath. Never operate a vehiclein an enclosed area withoutventing exhaust to the outside.

SAFETY INFORMATION

NOTE: Identifies tips, helpful hintsand maintenance information theowner/operator should know.

BEFORE YOU BEGIN

VENTILATION

If you work on the vehicle orsnowplow in a garage or otherenclosed area, be sure to ventexhaust gas directly to the outsidethrough a leakproof exhaust hose.

FIRE AND EXPLOSION

Be careful when using gasoline. Donot use gasoline to clean parts. Storeonly in approved containers awayfrom sources of heat or flame.

Park the vehicle on a levelsurface, place shift lever in PARKor NEUTRAL and set parkingbrake.

Leave the snowplow mounted onthe vehicle and lowered for mostservice procedures, unless toldotherwise.

PERSONAL SAFETY

Wear only snug-fitting clothingwhile working on your vehicle orsnowplow.

Do not wear jewelry or a necktie,and secure long hair.

Be especially careful near movingparts such as fan blades, pulleysand belts.

Wear safety goggles to protectyour eyes from battery acid,gasoline, dirt and dust.

Avoid touching hot surfaces suchas the engine, radiator, hosesand exhaust pipes.

Always have a fire extinguisherhandy, rated BC for flammableliquids and electrical fires.

HYDRAULIC SAFETY

Always inspect hydrauliccomponents and hoses beforeusing. Replace any damaged orworn parts immediately.

If you suspect a hose leak, DONOT use your hand to locate it.Use a piece of cardboard orwood.

WARNING

Lower blade when vehicle isparked. Temperature changescould change hydraulicpressure, causing the blade todrop unexpectedly or damaginghydraulic components. Failureto do this can result in seriouspersonal injury.

CAUTIONIndicates a situation that, if notavoided, could result in minorpersonal injury and/or damageto product or property.

WARNING

Hydraulic fluid under pressurecould cause skin injectioninjury. If you are injured byhydraulic fluid, get medicaltreatment immediately.

WARNING

Indicates a potentiallyhazardous situation that, if notavoided, could result in death orserious personal injury.

WARNING

Do not exceed GVWR or GAWRincluding blade and ballast. Therating label is found on thedriver-side vehicle doorcornerpost.

WARNING

Remove blade assembly beforeplacing vehicle on hoist.

WARNING

Gasoline is highly flammableand gasoline vapor is explosive.Never smoke while working onvehicle. Keep all open flamesaway from gasoline tank andlines. Wipe up any spilledgasoline immediately.

No. 21936 December 17, 2004

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SAFETY INFORMATION

BATTERY SAFETY

Please become familiar with and makeowners knowledgeable of the Warning andInstruction labels on the back of the blade!

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WARNING

CAUTION

LOWER BLADE WHEN VEHICLE IS PARKED.

REMOVE BLADE ASSEMBLY BEFORE PLACING VEHICLEON HOIST.

DO NOT EXCEED GVWR OR GAWR INCLUDING BLADEAND BALLAST.

READ OWNER'S MANUAL BEFORE OPERATING ORSERVICING SNOWPLOW.

TRANSPORT SPEED SHOULD NOT EXCEED 45 MPH.REDUCE SPEED UNDER ADVERSE TRAVELCONDITIONS.

PLOWING SPEED SHOULD NOT EXCEED 10 MPH.

SEE YOUR WESTERN OUTLET FOR APPLICATIONRECOMMENDATIONS.

59900

Warning Label CAUTION

Batteries normally produceexplosive gases which cancause personal injury.Therefore, do not allow flames,sparks or lit tobacco to comenear the battery. When chargingor working near a battery,always cover your face andprotect your eyes, and alsoprovide ventilation.

Batteries contain sulfuric acidwhich burns skin, eyes andclothing.

Disconnect the battery beforeremoving or replacing anyelectrical components. Instruction Label

No. 21936 December 17, 2004

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PRODUCT SPECIFICATIONS REQUIRED TOOLS

Hydraulic System

Plow Type

Crossover Relief Valve

Pressure (± 100 PSI)

No. of Turns Crossover Relief Valve

Is Backed Off (CCW) From Fully Seated*

Pump Relief Valve Pressure

(± 100 PSI)

Max. Motor Amp Draw At

Relief Pressure**

Standard, PRO-PLOW®, LSX 3500 1-1/2 – 2 1750 200

Heavyweight 3500 1-1/2 – 2 1900 210

Sport Utility 2500 2-1/4 – 2-3/4 1550 180

* Settings are approximate. ** Actual readings may vary due to vehicle battery voltage and oil temperature.

Solenoid Valve Coil Amp. Draw =1.5 Amp.

Motor Relay Coil Resistance =16 - 17 Ohms

Motor Relay Amp. Draw =0.7 Amp.

Headlamp Relay CoilResistance = 106 Ohms

Headlamp Relay Amp Draw =0.1 Amp.

Fuse Size

Harness – 6 Amp. (SFE-6)

Tools Required for servicing theelectrical and hydraulic systems:

Long/Slender Needle Nose Pliers

Flat Screwdriver

Socket and Combination Wrenches:3/8" thru 7/8", 1-1/16", 1-1/8"

ISARMATIC® SYSTEM SPECIFICATIONS

Hydraulic System

Hydraulic Fluid

WESTERN® High PerformanceFluid to -40°F (-40°C) or otherfluid conforming to militaryspecification MIL-H-5606A, suchas Mobil Aero HFA or ShellAeroShell® Fluid 4.

Automatic Transmission Fluid(ATF) Dexron® III to -10°F(-23° C).

Hydraulic Fluid Capacity

Unit Reservoir = 1 3/4 Quarts

System Total:

w/ 6" Ram = 2 1/8 QuartsSport Utility

w/ 8" Ram = 2 1/4 QuartsLSX

w/ 10" Ram = 2 3/8 QuartsStandard & PRO-PLOW®

w/ 16" Ram = 2 3/4 QuartsHeavyweight

Solenoid Valve Spool Travel =0.07" for three- and four-way valves(S2, S3)

Electrical System – approximatevalues:

Solenoid Valve Coil Resistance =6.7 Ohms at room temperature

Deep Socket: 7/8"

1/4" Socket or Nut Driver

12 V Test Light

Torque Wrench (in-lb)

Allen Wrench Set

3000 PSI Pressure Gaugew/adapter fittings

Flashlight

Pick Set

Hammer

Digital Volt/Ohm Meter

Pencil Magnet

Available from your WESTERN®

outlet:

UniMount® Electrical Tester

CAUTIONDo not mix different types ofhydraulic fluid. Some fluids arenot compatible and may causeperformance problems andproduct damage.

Mechanical

Fastener Torque (in-lb)

Pump Mounting Cap Screws.................... 175 – 185

Motor Terminal Nuts................................. 50 – 60

Motor Base Cap Screws .......................... 180 – 240

Motor End Cap Screws ............................ 35 – 45

Valve Manifold Cap Screws ..................... 55 – 60

Solenoid Cartridge Valve ......................... 120 – 144

Coil Nut .................................................... 48 – 60

Cartridge/Coil Cover Screws.................... 15 – 20

Base Lug Cap Screws.............................. 180 – 240

O-Ring Boss Plug..................................... 50 – 70

No. 21936 December 17, 2004

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ISARMATIC® HYDRAULIC HOSE ROUTING AND FITTING ORIENTATION

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No. 21936 December 17, 2004

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ISARMATIC® HYDRAULIC UNIT PARTS DIAGRAM

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ISARMATIC® HYDRAULIC UNIT VALVE IDENTIFICATION AND LOCATION

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VEHICLE HARNESS AND VEHICLE CABLE LOCATION

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SOLENOID CONTROL

Turn the vehicle ignition switch to theON or the ACCESSORY position.Move control ON/OFF switch to theON position. The control indicatorlight (red) should light whenever thecontrol ON/OFF switch and theignition (key) are both turned ON.

CAUTIONTo prevent accidental movementof the blade, always turn the ON/OFF switch to OFF whenever thesnowplow is not in use. Thecontrol indicator light will turnoff.

WARNING

The driver shall keep bystandersclear of the blade when it isbeing raised, lowered or angled.Do not stand between thevehicle and the blade, or within8 feet of a moving blade. Amoving or falling blade couldcause personal injury.

Turn the vehicle ignition switch on. Turn the control on. The control indicator light should be on.

Action Description of Operation

ON/OFF Slide the control power switch ON to activate the hydraulic system. Turn the control OFF to lockthe blade in place. This will prevent accidental movement of the blade.

Right Move the control lever right to angle the blade to the right.

Left Move the control lever left to angle the blade to the left.

Raise Move the control lever up (forward) to raise the blade to the desired height.

Lower/Float Move the control lever down (back) to lower the blade and activate the FLOAT mode.

To Cancel FLOAT The FLOAT mode can be canceled by either momentarily placing the control in the RAISEposition, turning the control off or turning the vehicle ignition off. Angling left or right will not cancelfloat.

OPERATING THE SNOWPLOW

No. 21936 December 17, 2004

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will glow red whenever the controlON/OFF switch and the vehicleignition switch are both ON.

3. Pressing the LOWER button for0.75 seconds will engage theFLOAT mode. The controlindicator FLOAT light will glowgreen.* Cancel the FLOAT modeby momentarily pressing theRAISE button.

Function Time Outs

All control functions, except forLOWER, automatically time out –stop – after a period of time. This isto prevent unnecessary battery drain.

The time-out period for the RAISEfunction is 2.4 seconds, while theangle function is 4.8 seconds.

The control will automatically turn offafter being idle for 20 minutes.

Smooth Stop

The control automatically allows theblade to coast to a stop. This resultsin smoother operation, reduces theshock to the hydraulic system andincreases hose and valve life.

1. Turn the vehicle ignition switch tothe ON or the ACCESSORYposition. The controller logo areawill become illuminated.*

2. Press the ON/OFF button on thecontrol. The control indicator lightwill glow red indicating the controlis on. The control indicator light

Button Description of OperationRight Press this button to angle blade to the right.

Left Press this button to angle blade to the left.

Raise Press this button to raise the plow and to cancel the float mode.NOTE: Plow will automatically stop raising after 2.4 seconds.

Lower/Float

Press this button to lower the plow. NOTE: After reaching the desired height, release the button.Holding the button down for more than 3/4 second will activate the float mode, indicated by greenFLOAT light.*

CancelFloat

The float mode can be cancelled by pressing the RAISE button, turning control off or turning vehicleignition off. Angling left or right will momentarily cancel float.

WARNING

The driver shall keep bystandersclear of the blade when it isbeing raised, lowered or angled.Do not stand between thevehicle and the blade, or within8 feet of a moving blade. Amoving or falling blade couldcause personal injury.

CAUTIONTo prevent accidental movementof the blade, always turn the ON/OFF switch to OFF whenever thesnowplow is not in use. Thecontrol indicator light will turnoff.

OPERATING THE SNOWPLOW

*Early models do not have FLOAT light or illuminated logo.

CABCOMMAND HAND-HELD CONTROL

No. 21936 December 17, 2004

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THEORY OF OPERATION

SNOWPLOW HEADLAMPS

The type of headlamp circuit varies,depending on the make/model/yearof vehicle and whether or not it isequipped with Daytime RunningLights (DRLs). The headlampswitching circuit uses two or morerelays. When combined with theplug-in headlamp harness, plow lightharness and vehicle harness, therelays automatically switch betweenvehicle and snowplow headlamps asthe harness plugs are connected anddisconnected.

Vehicles with Daytime RunningLights (DRLs) require a DRL kitwhich is an additional fused pink wireused in place of the brown wire.

SNOWPLOW PARK/TURNLAMPS

In an ordinary installation, thesnowplow Park/Turn lamps are wiredin parallel with the correspondingvehicle circuits. Some installations

on trucks with clearance lightsrequire an optional Park/Turn RelayKit which allows the snowplow parklamps to operate directly off thebattery, using the vehicle circuit topower only the relay. In either case,the vehicle and snowplow park andturn lamps will operatesimultaneously.

NOTE: The headlamp wiringschematics and electricalinformation included in this manualare typical for most 1998 and oldervehicles. For 1999 and newervehicles, refer to the snowplowinstallation instructions.

SNOWPLOW HYDRAULICS

The snowplow hydraulic systemperforms four blade movementfunctions. All functions require thevehicle ignition (key) switch to be inthe run position and the cab controlto be turned on.

The cab control supplies power tothe motor relay and the threesolenoid cartridge valves in variouscombinations to direct hydraulic fluidto the snowplow lift and anglecylinders or back to the reservoir.

Raise and angle functions requireboth the motor and solenoid cartridgevalve(s) to activate, while the lowerfunction only requires activation of asolenoid cartridge valve. The motorand valves are deactivated when thecab control button or lever isreleased. The high amperage motorpower circuit is completed throughthe battery cables when the motorrelay is activated. The motor relayand solenoid cartridge valve circuitsare low amperage, high side drive,and are completed when the cabcontrol is activated.

Proper operation of the snowplowhydraulic system depends on thevehicle's ability to provide adequateelectrical power. Electrical loadsfrom the snowplow, vehicle and

accessories can substantially reducethe vehicle system voltage if thecharging system cannot meet theelectrical demand. A low voltagecondition can cause intermittentsnowplow operation because themagnetic field produced in thesolenoid cartridge valve coils maynot be strong enough to shift thevalves. Because of many variables,it is impossible to determine the pointat which the system voltage is toolow to consistently operate thesnowplow. This condition can bedifficult to diagnose because the coilmagnetism can still be detected andno problem exists in the hydraulicsystem. Do not overlook the fact thatan apparent problem with thesnowplow can actually be caused bylow voltage in the vehicle electricalsystem. Consult a vehicle repairmanual for electrical systemspecifications.

No. 21936 December 17, 2004

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The following section containshydraulic and electrical schematics tohelp explain how the hydraulic unitperforms the different functions. Aschematic is an abstract drawingshowing the purpose of each of thecomponents in the system. Eachcomponent is represented by agraphical symbol. The hydraulic andelectrical legends list and describeeach of the symbols used in theschematics for this guide.

The first two schematics show ageneral overview of the completehydraulic and electrical systems.The remainder of the schematicshave been altered to highlight flow ofhydraulic fluid and electrical currentfor each function the hydraulic unitperforms or flow of electrical currentfor the snowplow and vehicle lights.

Bold lines represent the circuitbeing activated only.

Shaded components are eitheractivated or shifted from theirnormal position.

NOTE:Left side = Driver sideRight side = Passenger side

HYDRAULIC AND ELECTRICAL SCHEMATICS

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Wire Color Code AbbreviationsBLK Black BRN/GRN Brown w/ Green LTBLU Light Blue PUR Purple DRL Daytime Running LightsBLK/ORN Black w/ Orange BRN/RED Brown w/ Red LTGRN Light Green RED Red MTR RLY Motor RelayBLK/RED Black w/ Red DKBLU Dark Blue LTBLU/ORN Light Blue w/ Orange TAN Tan P/T SIG Park/Turn SignalBLK/WHT Black w/ White DKBLU/ORN Dark Blue w/ Orange LTBLU/WHT Light Blue w/ White VIO VioletBLU Blue DKBLU/WHT Dark Blue w/ White ORN Orange WHT WhiteBLU/ORN Blue w/ Orange GRN Green ORN/BLK Orange w/ Black WHT/YEL White w/ YellowBRN Brown GRY Gray PNK Pink YEL Yellow

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NOTE: All relays are shown in thede-energized state.

ELECTRICAL SCHEMATIC – 9-PIN HARNESS (’98 AND OLDER VEHICLES)

NOTE: DRL kit not shown.

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ELECTRICAL SCHEMATIC – 12-PIN HARNESS (’98 AND OLDER VEHICLES)

NOTE: DRL kit shown.

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HYDRAULIC SCHEMATIC

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ANGLE RIGHT – ELECTRICAL

Blade Movement: Angle Right

Controller: Right

System Response:

1) By moving control lever orpressing the controller button, thecircuit board within the cab

control supplies power for theelectrical circuit.

2) Electrical current flows throughthe motor relay, activating thepump motor, and solenoidcartridge valve S2, shifting itsspool.

3) Hydraulic fluid from the pumpflows through the inlet checkvalve, solenoid cartridge valve S3and the poppet check valve, andinto the base end of the leftcylinder, causing it to extend.

4) The retracting right cylinderpushes the hydraulic fluid out ofits base end, through solenoidcartridge valves S2 & S3 back tothe reservoir.

No. 21936 December 17, 2004

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ANGLE RIGHT – HYDRAULIC

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ANGLE LEFT – ELECTRICAL

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Controller: Left

System Response:


4) Pressure within the hydrauliccircuit shifts the spool, openingthe poppet check valve.

5) The retracting left cylinder pushesthe hydraulic fluid out of its baseend, through the open poppetcheck valve and solenoidcartridge valve S3 and back tothe reservoir.

3) Hydraulic fluid from the pumpflows through the inlet checkvalve and solenoid cartridgevalves S3 & S2, and into the baseend of the right cylinder, causingit to extend.


2) Electrical current flows throughthe motor relay, activating thepump motor, and solenoidcartridge valves S2 & S3, shiftingboth spools.

No. 21936 December 17, 2004

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ANGLE LEFT – HYDRAULIC

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No. 21936 December 17, 2004

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RAISE – ELECTRICAL

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control supplies power for theelectrical circuits.

2) Electrical current flows throughthe motor relay, activating thepump motor, and solenoidcartridge valve S3, shifting thespool.

3) Hydraulic fluid from the pumpflows through the inlet checkvalve, solenoid cartridge valvesS3 & S2 and the internal checkvalve in solenoid cartridge valveS1, and into the lift cylindercausing it to extend.

No. 21936 December 17, 2004

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RAISE – HYDRAULIC

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No. 21936 December 17, 2004

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Blade Movement: Lower / Float

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2) Electrical current flows throughsolenoid cartridge valve S1,shifting the spool.

3) The weight of the plow forces thelift cylinder to retract. Theretracting lift cylinder pushes thehydraulic fluid through solenoidcartridge valves S1 & S2 & S3,and back to the reservoir.

NOTE: CabCommand hand-heldcontrol only – while in FLOAT,angling right or left will temporarilycancel float (turn off solenoidcartridge valve S1) until the anglebutton is released.

No. 21936 December 17, 2004

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LOWER – HYDRAULIC

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No. 21936 December 17, 2004

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HOLD IN RAISED POSITION – HYDRAULIC

Blade Movement: Hold in Raised Position

Controller: None

System Response:

1) Hydraulic fluid is trapped in the liftcylinder by the internal checkvalve in solenoid cartridge valveS1.

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No. 21936 December 17, 2004

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STRIKING AN OBJECT WHILE PLOWING – RIGHT HYDRAULIC CYLINDER RETRACTS

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Blade Movement: Striking an Object While Plowing

Controller: None

System Response:

1) Hydraulic fluid is trapped in thebase end of the cylinders by therelief valves, the poppet checkvalve and solenoid cartridgevalve S2.

2) When the plow contacts anobject, the force of the impactincreases the hydraulic pressurein the base end of the cylinder.When the pressure exceeds therelief valve pressure setting, therelief valve opens allowing fluid toflow to the base of the oppositecylinder.

No. 21936 December 17, 2004

28

STRIKING AN OBJECT WHILE PLOWING – LEFT HYDRAULIC CYLINDER RETRACTS

Blade Movement: Striking an Object While Plowing

Controller: None

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1) Hydraulic fluid is trapped in thebase end of the cylinders by therelief valves, the poppet checkvalve and solenoid cartridgevalve S2.

2) When the plow contacts anobject, the force of the impactincreases the hydraulic pressurein the base end of the cylinder.When the pressure exceeds therelief valve pressure setting, therelief valve opens allowing fluid toflow to the base of the oppositecylinder.

No. 21936 December 17, 2004

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HEADLAMPS – PLOW NOT CONNNECTED – 9-PIN (’98 AND OLDER VEHICLES)


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NOTE: 3-relay system only.


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No. 21936 December 17, 2004

35

TROUBLESHOOTING GUIDE

How to Use the Troubleshooting GuideIntroduction

This guide consists of a series oftables, diagrams, flow charts andother information. When usedproperly it will assist the mechanic inidentifying and repairingmalfunctioning system components.Western Products highlyrecommends the use of theUniMount® Electrical Tester as atimesaving option for electricalsystem diagnosis. When using thistester, refer to the supplied instructionmanual for proper use of the tester.

Any malfunction of the snowplow canbe categorized as either mechanical,electrical or hydraulic. Mechanicalissues are generally related to theblade, framework and mountcomponents and are usually identifiedby visual inspection. Electrical andhydraulic issues can sometimes bedifficult to trace to the componentlevel and that is the purpose of thistroubleshooting guide.

Read and understand the Theoryof Operation before attemptingtroubleshooting.

When diagnosing the snowplowelectrical and hydraulic systems,many variables need to be eliminatedin order to obtain workable testprocedures. These variablestranslate into conditions listed beforethe tables or flow charts and must besatisfied before proceeding.

If the listed conditions are not met,the procedure can result in inaccurateresults and wasted time.

In many cases, satisfying the listedconditions alone will solve theproblem.

1. Go to the General DiagnosticTable and satisfy the nine listedconditions. These conditionsmust be met before proceedinginto the table or to anysubsequent test.

2. Locate the condition in the tablewhich best describes the problemand check possible causes andactions in the order listed.

3. Proceed to a service procedure,another condition, or a specifictest as directed. All tests exceptthe Hydraulic System Test use aflow chart format. To use theseflow charts, first satisfy any listedconditions at the top of the page.

Then begin at the upper leftsquare and proceed as directed.

4. Follow along sequentially throughthe table and tests, referring tothe hydraulic and electricalschematics in the Theory ofOperation section and thecomponent Identification andLocation diagrams. Eventuallythe problem will be pinpointed atthe component level.

Electrical Testing

Read and understand the Theory ofOperation section. A simple 12V testlight with a ground lead can be usedfor circuit testing. When directed tocheck for 12 volts (12V), ground thetest lamp lead and probe theterminal. When asked to check forground, attach the test lamp lead to+12V and probe the terminal. Notethat 12V is a nominal value. If usinga voltmeter, actual voltage will varywith the vehicle and presence ofloads in tested circuits. Continuityalone does not guarantee a goodcircuit. Poor connections ordamaged wires may have continuitybut be unable to carry sufficientcurrent.

Troubleshooting Guide Contents

General Diagnostic Table ............... 36Packing Nut Adjustment ................ 39Motor Test ...................................... 40Motor and Motor Relay Test

Diagram ............... 41Motor Relay Test ............................ 42Vehicle Harness Test –

Motor Relay ......... 43Control Test ................................... 44Pump Pressure Test ...................... 46Cartridge Coil Activation Test ......... 48Vehicle Harness Test –

Cartridge Coils ..... 49Hydraulic System Test ................... 50Crossover Relief Valve Inspection

and Adjustment .... 51Poppet Valve Inspection ................ 52Individual Solenoid Coil Test .......... 53Solenoid Cartridge Valve

Inspection ............ 53Headlamp Test Diagram – 9-Pin .... 54Vehicle Headlamp Test – 9-Pin ...... 55Plow Headlamp Test – 9-Pin .......... 56Plow Park/Turn Lamp Test –

9- or 12-Pin ........... 57Optional Park/Turn Relay Kit Test ... 58Optional Park/Turn Relay Kit

Schematics .......... 59Vehicle Headlamp Test – 12-Pin .... 60Plow Headlamp Test – 12-Pin ........ 62Headlamp Test Diagram – 12-Pin ... 64

No. 21936 December 17, 2004

36

GENERAL DIAGNOSTIC TABLE

BEFORE USING THIS GENERAL DIAGNOSTIC TABLE OR PERFORMING ANY TESTS, YOU MUST VERIFY THE FOLLOWINGCONDITIONS:

CAUTIONDo not mix different types ofhydraulic fluid. Some fluids arenot compatible and may causeperformance problems andproduct damage.

1. Snowplow is attached to vehicleand all harnesses are connected.

2. Harness connector pins andterminals are free of corrosion,insuring good connections, andcoated with dielectric grease.

3. Vehicle battery and chargingsystem are in good condition andbattery connections are clean andtight.

4. Hydraulic reservoir is filled to fillerplug level with recommendedfluid, when lift cylinder is fullyretracted. See ProductSpecifications.

5. There are no fluid leaks fromhoses, fittings, cylinders or thehydraulic unit.

6. All built up snow and ice isremoved from the snowplow.

7. 6 amp fuse* in vehicle harness isgood.

8. Ignition is turned on or engine isrunning.

9. The control is connected in thecab and turned on.

*Early revision harnesses may have a10 amp fuse.

CONDITION POSSIBLE CAUSE ACTION

Motor does not run for any requested function. Poor connections in vehicle or snowplow battery cables.

Clean and re-establish connections.

Motor worn or damaged or pump seized. Go to Motor Test.

Motor relay inoperative. Go to Motor Relay Test.

Open circuit in vehicle wiring harness. Go to Vehicle Harness Test - Motor Relay.

Malfunctioning controller. Go to Control Test.

Motor runs continuously. Motor relay sticking or always energized. Go to Motor Relay Test.

Short circuit in vehicle wiring harness. Go to Vehicle Harness Test - Motor Relay.


Snowplow won’t raise – motor runs. Lift cylinder packing nut too tight. Adjust lift cylinder packing nut.

Clogged pump filter (all functions are affected). Clean or replace filter, flush reservoir.

Worn or damaged pump. Go to Pump Pressure Test.

Poor connections on battery cables. Inspect battery cables, clean and re-attach all connections.

No. 21936 December 17, 2004

37



Snowplow won’t raise – motor runs. (cont.) Solenoid valve coil not activating properly. Go to Solenoid Coil Activation Test.

Hydraulic system malfunction. Go to Hydraulic System Test.


Snowplow raises slowly or partially – motor runs. Lift cylinder packing nut too tight. Adjust lift cylinder packing nut.

Clogged pump filter (all functions are affected). Clean or replace filter, flush reservoir.

Worn or damaged pump. Go to Pump Pressure Test.

Poor connections on battery cables. Inspect battery cables, clean and re-attach all connections.

Quill adjusted in too far. Adjust quill out.


Snowplow will not lower or lowers slowly, or won’t Quill adjusted in too far. Adjust quill out.

float. Lift cylinder packing nut too tight. Adjust lift cylinder packing nut.

Lift cylinder packing dried out. Loosen packing nut, lubricate rod, operate cylinder until it moves easily, adjust packing nut.

Solenoid valve coils not activating properly. Go to Solenoid Coil Activation Test.



Snowplow lowers by itself or won’t stay in raised Solenoid valve coils not activating properly. Go to Solenoid Coil Activation Test.

position. Hydraulic system malfunction. Go to Hydraulic System Test.


Blade will not hold angled position. Air in angle cylinders. Cycle angle functions to purge cylinders.

Fluid bypassing cylinder relief valve. Go to Relief Valve Inspection and Adjustment.


Plow does not perform the selected function or performs a different function.

Hydraulic hose routing incorrect. Verify correct hose installation. See Hose Routing Diagram.

Solenoid valve coils not activating properly. Go to Solenoid Coil Activation Test.


Malfunctioning Controller. Go to Control Test.

No. 21936 December 17, 2004

38



Vehicle harness 6 amp fuse blows. Red wire in vehicle harness is shorted to ground. Repair wire or replace vehicle harness.

Motor relay primary coil shorted internally. Check primary coil with ohmmeter. Replace defective motor relay.

Solenoid valve coil shorted internally. Go to individual coil test. Replace shorted coils.

Motor relay or solenoid coil wires in vehicle harness shorted to ground.

Repair wire or replace vehicle harness.

Solenoid coil wires in plow harness shorted to ground.

Repair wire or replace plow harness.


Vehicle accessory fuse blows. Circuit overloaded. Consult vehicle owner’s manual for correct application of aftermarket electrical loads.

Excessive load on vehicle electrical system while using snowplow.

Poor connections in battery cables. Inspect battery cables, clean and re-establish all connections.

Angle or lift cylinder packing nut too tight. Adjust cylinder packing nut.

Worn or damaged pump or motor. Go to Pump Pressure Test/check motor.

Burned out bulbs or corroded sockets. Replace bulbs, clean contacts.

Wires improperly connected to relays. Review and correct wire installation. See Headlamp Test Diagram.

Snowplow headlamps operate irregularly or not at all – snowplow attached.

-or- Vehicle headlamps operate irregularly or not at all –snowplow removed.

Headlamp relay inoperative. Go to Plow Headlamp Test or Vehicle Headlamp Test.

Vehicle daytime running lamps (DRLs) do not work – snowplow removed. ('98 and older vehicles)

Parking brake on. Fully release parking brake.

Power in DRL circuit has been interrupted. Turn lamp and/or ignition switch on and off to cycle the DRL circuitry.

No output from DRL module. Repair vehicle electrical system.

Blade will not hold position. Hydraulic system malfunction. Go to Hydraulic System Test.

Snowplow Park or Turn lamps operate intermittently or not at all – snowplow attached.

Burned out bulb, corroded socket(s) or poor electrical connection.

Replace bulbs/clean contacts. If necessary, go to Park/Turn Lamp test.

No. 21936 December 17, 2004

39

PACKING NUT ADJUSTMENT

Periodically verify the lift cylinder andangle cylinder packing nuts have notloosened. If a packing nut is loose orexcessive leakage appears whenactivating the cylinder, tighten thepacking nut 1/4 turn maximum afteryou feel the packing nut contact thepacking.

CAUTIONDo not overtighten the packingnut. Over-tightening affectsplow operation and the life of thepacking.

NOTE: A small amount of leakageis necessary to properly lubricatethe cylinder rod.

The lift or angle cylinder packingsmay dry out if the plow is not used fora period of time. If the lift arm isdifficult to push completely downwhen the control is in float, or theplow angles slowly and causesexcessive load on the motor, loosenthe lift or angle cylinder packing nuts,lubricate the cylinder rods with oil andcycle the plow using the control.When the packings are lubricated,tighten the packing nuts and recheckoperation.

No. 21936 December 17, 2004

40

MOTOR TEST

Refer to the Motor and Motor RelayTest Diagram.

Retest with jumper cable frombattery (+) to (+) motor

terminal. Does motor run?

YES YES Go to MotorRelay Test.

YES Momentarily attach (+)jumper cable between batteryand motor side of motor relaysecondary. Does motor run?

Check for binding in pump.Replace pump, or repair or

replace motor.

NO

NO

Repair ground (black) wire invehicle or plow battery cable.

NO

Repair positive (black/red) wirein vehicle battery cable or plow

battery cable.

Momentarily attach jumper cablesfrom the battery to respective (+)

and (-) motor terminals. Doesmotor run?

WARNING

The driver shall keep bystandersclear of the blade during thistest. Do not stand between thevehicle and the blade. A movingor falling blade could causepersonal injury.

No. 21936 December 17, 2004

41��

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DIAGRAM INSIDE COVER

* Later revision harness only.Early revision harness has a single black/orange wire tomotor relay only, unless modified for use with hand-heldcontrol.

** Early production motors use cap screw and star washer.Current production motors have a stud.

No. 21936 December 17, 2004

42

MOTOR RELAY TEST

1. Jumper power and ground directlyfrom battery to motor to verify thatthe motor runs. Make finalconnection at the motor.

2. Refer to the Motor and MotorRelay Test Diagram, and VehicleHarness and Vehicle CableLocation Diagram.

Motor does not run:Attach a jumper wire

from battery (+) to motorrelay primary terminalwith brown/red wire.

Does motor run?

Repair or replace red (+) cablefrom battery to motor relay.

Is the primary terminal groundwire black/orange

(early revision harness)?

NOYES YES

NO

YESNO

NO

YESMotor runs continuously:

NO

Disconnect brown/red wirefrom motor relay primaryterminal. Does the motor

stop?

Replace motor relay.

YES Verify correct polarity ofcables from battery to

motor.

Go to Control Test.

Replace motor relay.

WARNING


Momentarily attach a jumpercable across the motor relay

secondary terminals.Does motor run?

Leave (+) jumper wire attachedand attach a ground jumperwire from battery (-) to relayprimary terminal with black/orange or orange/black wire.

Does motor run?

Leave (+) jumper wire attachedand remove ground jumper

wire. Unplug vehicle harnessconnector and apply ground to

socket #5 on vehicle side. Does motor run?

Black/orange wire in vehicleharness is open. Repair wire or

replace harness.

Repair or replaceorange/black wire

between motor relay andbattery (-).

Black/orange wire in plowharness is open. Repair wire or

replace harness.

Go to Vehicle Harness Test -Motor Relay. If OK, go to

Control Test.

Reverse leads or replace cableif manufactured incorrectly.

NO

YES

YES

NO

No. 21936 December 17, 2004

43

VEHICLE HARNESS TEST – MOTOR RELAY

1. Perform the Motor Test and MotorRelay Test first.

2. Disconnect the control in the cab.

3. Refer to the 6-Pin Connectordiagram. Test the vehicle side ofthe connector in the cab asfollows.

YES

NO

NO

YESIs there 12V at socket #1?

Install a jumper wirebetween sockets #1 and#4. Does motor run?

Brown/red wire to motorrelay is open. Repair wire

or replace harness.

Verify vehicle powersource and 6 amp fuse* inred wire. Repair red wire

or replace harness.

Remove jumper wire. Goto Control Test.

*Early revision harnesses may have a 10 amp fuse.

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No. 21936 December 17, 2004

44

a. S1 output will be ON if control is in float. Activate raise function to cancel float. Ifhand-held control is in float, S1 output will turn off while angle button is pressedand on when the button is released.

b. For hand-held control, motor relay output turns off before solenoid coil outputswhen button is released.

c. For hand-held control, outputs turn off after button is held for approximately 5seconds.

d. For hand-held control, outputs turn off after button is held for approximately 2.5seconds.

e. Solenoid control activates S1 output in float when lever is moved to lower position.Hand-held control activates float when lower button is held for .75 second.

Test Procedure for Hand-Held or Solenoid Control

1. Disconnect the control in the caband remove to work bench.

2. Refer to the 6-Pin Connectordiagram and the chart.

3. Using a 12V power source with a 6amp fuse in the positive lead,carefully apply +12V to pin #1 andground to pin #3 of the 6-pinconnector.

CONTROL TEST

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4. Turn the control on. Powerindicator lamp should be lit. Usinga grounded test light, check for12V at each of pins #2, 4, 5, 6when the control is activated foreach function. Footnotes in thechart indicate special conditions ofcontrol operation.

5. Compare the control outputs for allfunctions with the chart andproceed to the flow diagram.

PinNo.

PurposeAngle

Right (c)Angle

Left (c)Raise (d)

Lower/Float (e)

1 12V Input

2 S2 Output (3-Way) ON ON

3 Ground

4 Motor Relay Output ON (b) ON (b) ON (b)

5 S3 Output (4-Way) ON ON

6 S1 Output (2-Way) (a) (a) ON

No. 21936 December 17, 2004

45

Do control outputsmatch chart for allfunctions?

Solenoid Control:replace PCB or controlassembly

Hand-Held Control:follow handlinginstructions. Removehandle half. Is the whitecord connector fullyseated on the PCB?

Control is OK. Verifyvehicle harness groundand power source forred wire.

Seat the cordconnector fullyon the PCB.Retest Control.

Yes

No

Replace PCB

Carefully disconnect white cordconnector from PCB. Test the cordfor continuity according toelectrical schematics. Note internalconnection in the cord. Doescontinuity match schematic?

Yes No

Yes No

Replace coil cord

To Safely Handle Hand-Held PCB:

CONTROL TEST

CAUTIONPrinted circuit board (PCB) issubject to damage from staticelectricity. Follow instructionsbelow to safely handle PCB.

1. Disconnect the control in the caband remove to a workbench.

2. Place control on its left side andremove right side of handle,leaving the keypad/circuit boardassembly in left half.

3. Touch hand to any grounded metalobject to discharge possible staticbuildup.

4. Remove keypad/circuit boardassembly from housing by onlytouching the edges of the keypad/circuit board assembly.

5. The keypad/circuit boardassembly can be handled safelyas long as contact with it ismaintained.

NOTE: For hand-held control, poorground connections or high or lowvoltage will shut the control off.

No. 21936 December 17, 2004

46

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1. Lower blade to the ground and fullycollapse the lift cylinder.

2. Carefully remove the 1/4" pipe plugfrom the lift cylinder test port in thehousing above the manifold block.Be aware of possible residualpressure in the lift cylinder.

3. Using a suitable adapter fitting,attach a 3000 psi hydraulicpressure gauge to the lift cylindertest port.

4. Activate the raise function with thecontrol and read the pump reliefpressure when the blade is fullyraised.

5. Refer to the illustration below forpump relief valve screw and liftcylinder test port location. Thechart lists relief pressure settings.

6. Proceed to the flow chart on thefollowing page.

NOTE: Adjusting pump relief valve screwclockwise 1/4 turn increases relief pressureapproximately 225 PSI. Early 2-piece die-cast pumps may require removal to adjust.

WARNING

The tester shall keep bystandersclear of the blade during thistest. Do not stand between thevehicle and the blade. A movingor falling blade could causepersonal injury.

PUMP PRESSURE TEST

Plow Type Maximum Motor Amp Draw

At 11.2 Volts w/Warm Oil

Pump Relief Valve Pressure

(± 100 PSI)

Standard, PRO-PLOW® 200 1750

Heavyweight 210 1900

Sport Utility 180 1550

No. 21936 December 17, 2004

47

PUMP PRESSURE TEST

NO

NOYES

YES YES

Is motor amp draw greater thanchart value when pump atspecified relief pressure?

Repair orreplacemotor.

Go toHydraulic

System Test.

Go to Cartridge CoilActivation Test. Repairas necessary and re-check pump pressure.

NO

NO

Does pump relief pressurematch value on chart?

Replacepump.

Turn pump pressure reliefscrew clockwise to increasepressure. Can pressure beadjusted to value in chart

above?

Is the pump pressurezero?

NO

Inspect pumpO-ring beneath pump.

Replace if damaged. Canthe pressure now be

adjusted to chart value?

YES

YES

On 3-piece pumps, verify the reliefvalve screw cannot be turned by

hand. If it can, adjust to chart valueafter applying medium strength

thread locking compound to screwheads or stake pump body with

punch around threads to preventscrew loosening.

No. 21936 December 17, 2004

48

CARTRIDGE COIL ACTIVATION TEST

1. Disconnect the black/red (+)battery cable from the motor andisolate it.

2. Verify wires are properly attachedto solenoid coils. Refer to WireConnection Table, ElectricalSchematic, and Solenoid CartridgeValve Identification and Location.

3. Activate the control for eachfunction and check for magneticpull at all three solenoid valvecoils. Only the coils designatedas "ON" in the table shouldactivate for each function. Afternoting which coils are energized,proceed to the flow chart.

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Cartridge Coil Wiring and Activation – Wire Connection Table

SolenoidCoil

PlowHarness

PinWire Color

AngleRight

AngleLeft

Raise Lower

S1 (2-Way) 1 White/ Yellow * * * ON

S2 (3-Way) 3 Light Green ON ON

S3 (4-Way) 4 Light Blue ON ON

*S1 output will be “ON” for all functions if control is in “FLOAT”.Activate “RAISE” function to cancel “FLOAT”.

Hand Held Control Only – While in “FLOAT”, pressing and holding the “RIGHT”or “LEFT” button will turn off the solenoid cartridge valve S1 until thebutton is released.

Do activated coils match thechart for all functions?

Verify battery cables are connected. Is thereground at all black/orange wires attached to coils?

Repair black/orange wires to coils, checkground connections at motor, battery cableconnector and battery (-) terminal. Retest.

NONO

YES YES

Go to Hydraulic System Test.

Disconnect 9- or 12-pin harness at front of vehicle.Apply 12V to the white/yellow, light blue and light greenwires at coils S1, S2 and S3. Does each coil activate?

Go to Individual Coil Test.Replace open coils.

NO

YES

YES

Go to Vehicle Harness Test for Cartridge Coils.

NO

Respective wire is open or hasbad connection. Repair wire or

replace plow harness.

Apply 12v to pins #1,3 and 4 of the plow harnessconnector. Do the respective coils activate

according to the chart?

No. 21936 December 17, 2004

49

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VEHICLE HARNESS TEST – CARTRIDGE COILS

1. Disconnect the black/red (+)battery cable from the motor andisolate it.

2. Perform Cartridge Coil ActivationTest.

3. Connect all harness connectorsat the front of the vehicle.

4. Refer to the 6-Pin Connectordiagram for socket location.

YESYES

NO NO

Verify 6 amp fuse* and red wireconnection to vehicle circuit.

Repair wire or replace harness.Replace fuse as needed.

YES NO

Is there ground at socket #3? Is there 12v at socket #1? Attach a jumper wire between terminal #1 andterminals #6. Does solenoid coil S1 activate?

Repeat process between terminal #1 and #2, andbetween terminal #1 and terminal #5. Do solenoid

coils S2 and S3 activate respectively?

Orange/black wire is openbetween connector and motor

relay or battery (-). Repairwire or replace harness.

Go to Control Test Corresponding wire isopen or has poor

connection. Repair wire orreplace vehicle harness.

*Early revision harnesses may have a 10 amp fuse.

No. 21936 December 17, 2004

50

HYDRAULIC SYSTEM TEST

This test consists of trying all theplow functions and comparing theplow reaction to the action requestedin the following table. The table willpinpoint a solenoid valve or poppetcheck valve problem accurately ifonly one component ismalfunctioning. If the plow reactionfor a given function is not listed inthe table, there may be a crossoverrelief or poppet check valve which is

stuck open or contaminated, missingor damaged O-rings or backing ringson cartridge, crossover relief orpoppet check valve spool, or theremay be two or more malfunctioningcomponents. In this case, use thespecific function hydraulic schematicand carefully inspect eachcomponent in the flow circuit. Ifcontamination is evident in morethan one component, the hydraulic

unit, hoses and cylinders must becompletely disassembled, inspectedand cleaned.

1. Perform Cartridge Coil ActivationTest first.

2. Verify hydraulic hose installationis correct. Refer to the HoseRouting diagram.

3. Test all of the plow functions.

4. Inspect and clean or replace thesuspected component. Refer tothe Hydraulic Unit Parts Diagram.

5. Refer to the sections followingthe table for inspection andadjustment of solenoid cartridgevalves, poppet check valve andcrossover relief valves.

IMPORTANT: When testing the plowfunctions, be sure the control is notin “float.”

ACTION REQUESTED PLOW REACTION POSSIBLE CAUSE

Angle Left S3 stuck shiftedAngle Right

None S2 not shifted

Poppet check valve not opening

Angle Right S3 not shifted

Raise S2 not shifted

Angle Left

None S2 and S3 not shifted

Poppet check valve not opening

None S3 not shiftedRaise

Angle Left S2 stuck shifted

None (blade raised) Lowers S1 stuck shifted or has leaking internal check valve

S1 not shifted

S2 stuck shifted

Lower None

S3 stuck shifted

Drifts Right S2 stuck shifted

Contamination or damaged O-rings in crossover reliefvalve

Drifts Left Poppet check valve open

None

Contamination or damaged O-rings in crossover reliefvalve

No. 21936 December 17, 2004

51

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CROSSOVER RELIEF VALVE INSPECTION AND ADJUSTMENT

Crossover Relief Valve Inspection

1. Remove the valve stem, ball,spacer and spring.

2. Look for broken or damagedparts, contamination or missing ordamaged O-rings.

CAUTIONBe careful to strike the stemsquarely. You can bend the stemif you do not strike it squarely.

3. If parts are in good condition,place ball on hard wood block,hold stem seat on ball, and strikestem lightly with a hammer. Thiswill re-conform the seat to theball.

4. Apply a light coat of anti-seize orgrease to stem threads. LubricateO-ring with hydraulic fluid.Reassemble components intovalve block.

Crossover Relief Valve SettingsAdjustment

1. Adjust by tightening the reliefvalve stem until it bottoms out(until spring is fully compressed).

2. Back off valve stem (rotatecounterclockwise) the number ofturns indicated in the CrossoverRelief Valve Settings chart.

Plow Type No. of Turns Backed Off

(CCW) From Fully Seated* Crossover Relief Valve

Pressure (± 100 PSI)

Standard, PRO-PLOW® 1-1/2 – 2 3500

Heavyweight 1-1/2 – 2 3500

Sport Utility 2-1/4 – 2-3/4 2500

* Settings are approximate.

No. 21936 December 17, 2004

52

POPPET CHECK VALVE INSPECTION

Poppet

Spool

Back-Up Ring

O-Ring

O-Ring BossPlug O-Ring

Spring

Spring

O-Ring BossPlug

O-Ring

1. Remove O-ring boss plug, springand poppet.

NOTE: Strike boss plugs squarelywith a hammer to facilitate removal.

2. Remove O-ring boss plug, springand spool with O-ring. Use long/slender needle-nosed pliers toremove spool.

3. Inspect springs, poppet, spool,O-rings and poppet seat* forwear, damage or contamination.

4. If the valve manifold block has asteel poppet seat, use a strongpencil magnet to push and pull onthe seat. If the seat moves at all,replace the valve block.

5. Re-oil O-rings, install spool fullyinto bore. Spool must insertsmoothly.

6. Install poppet, springs and O-ringboss plugs. Torque O-ring bossplug to 60 in-lb.

* Early valve manifolds have thepoppet seat machined into theblock. Current valve manifolds usea pressed-in steel poppet seat.

No. 21936 December 17, 2004

53

Apply 12Vand groundto coil

Cartridge valveidentificationmarked on hex

Watch here

Probe here

SOLENOID CARTRIDGE VALVE INSPECTION

1. Remove coils from the solenoidcartridge valves and remove thecartridge valves from the manifold.Look for visible contamination ordamaged seals. Check for stuckspools with a plastic, aluminum, orsoft brass probe by pushing on thespring loaded internal spool fromthe end of the valve. The spoolshould move freely through itsentire travel. Spool travel isapprox. 0.070".

NOTE: Using probe to move spoolmay shear contamination which wasaffecting spool movement.

2. Bench test the cartridge valve byinstalling a coil on the stem andapplying 12V and ground. Watchthrough the side ports for internalspool travel.

If the cartridge valve spool isstuck or its travel is restricted,replace the cartridge. If thecartridge valve appears to be ingood condition, clean it with partscleaning solvent and dry withcompressed air, being careful notto damage the seals. Check thespool travel again in case anyinternal contaminants weredislodged during cleaning.Re-oil the cartridge valve seals

and o-rings and reinstall thecartridge valve, torquing to10 ft-lb. Install the coils and torquethe retaining nuts to 4 ft-lb.

NOTE: If contamination is seen inmore than one component, it canreasonably be assumed that theentire system is contaminated. Inorder to perform a proper repair, theentire hydraulic unit, includinghoses and cylinders, must bedisassembled and cleaned. Thesource of the contamination mustbe located and repaired beforereassembly.

1. Remove both wires from coilterminals.

2. Attach an ohmmeter across thecoil terminals.

3. A reading of approximately 6.7ohms indicates the coil is good.

NOTE: A good coil will drawapproximately 1.5 amps.

INDIVIDUAL SOLENOID COIL TEST

No. 21936 December 17, 2004

54

HEADLAMP TEST DIAGRAM – 9-PIN HARNESS (’98 AND OLDER VEHICLES)

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NOTE: DRL applicationsrequire a DRL kit. DRL kitnot shown.

No. 21936 December 17, 2004

55

VEHICLE HEADLAMP TEST – 9-PIN HARNESS

1. Verify correct harness and wireinstallation to relays and vehicleheadlamps. See the HeadlampTest Diagram – 9-Pin Harness.The specific wiring diagram forthe vehicle can be found in the

plow installation instructions, theWESTERN® UniMount® ServiceManual Vol. 2., or (for ’98 andolder vehicles) the manualHeadlamp Electrical Schematicsfor Straight Blades.

2. Turn ignition and headlight switchon.

3. Disconnect all harnesses at thefront of the vehicle.

4. All bulbs must be good.

At each relay, is there 12V at terminal30 with green (high beam) or yellow

(low beam) wires?

Is there 12V at terminal 87awith red (high beam) or orange

(low beam) wires?

Unplug plug-in harnessconnectors at each vehicleheadlamp. Is there 12V at

the red wire (high beam) andorange wire (low beam)?

Red or orange wiresopen in plug-in

harness. Repair wireor replace harness.

YES

NO

NO

Check vehicle output fromheadlight connector to plug-in

harness. Repair vehiclesystem or open wires in plug-

in harness.

Carefully disconnect theblack/orange wire from terminal85 of both relays. Is there now

12V at terminal 87a?

Blue ground wire inplug-in harness isopen. Repair wireor replace harness.

NO NO

YES

Black/orange wire in vehicleharness is shorted to ground.

Repair wire.

Replace relay.

YES

YES

No. 21936 December 17, 2004

56

PLOW HEADLAMP TEST – 9-PIN HARNESS

1. Verify correct harness and wireinstallation to the headlamprelays.


3. Connect all harnesses at the frontof the vehicle.

4. Turn vehicle headlamp switch on.For vehicles with DaytimeRunning Lamps (DRLs), turnignition on. DRL equippedvehicles have a pink wire instead ofa brown wire on relay terminal 86.

5. Refer to the 9-Pin ElectricalSchematic Headlamp TestDiagram – 9-Pin Harness, andConnector diagram. The specificwiring diagram for the vehicle can

be found in the plow installationinstructions, the WESTERN®

UniMount® Service Manual Vol. 2.,or (for ’98 and older vehicles) themanual Headlamp ElectricalSchematics for Straight Blades.

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NO

YES

NONO

YES

YES

NO

NO YES

NO

YES

NO

YES

YES

YES

NO

NO

At each headlamp relay, is there12V at terminal 30 with green (highbeam) or yellow (low beam) wires?

Is there 12V at terminal 87?With white (high beam) orblack (low beam) wires.

Is there 12V at the black or whitewires in the plow headlamp

connectors at the bulb?

Check vehicle output fromheadlamp connector to plug-in

harness. Repair vehicle electricalsystem or open wires in plug-in

harness.

Is there 12V at each relay terminal86 with brown or (DRL) pink wire?

Check brown wire connection tovehicle park lamp circuit or (DRL)

pink wire fuse or connection tovehicle accessory wire or fusebox.Repair or replace open (DRL) pink

or brown wire.

Disconnect 9-pin connector. Attachground jumper to relay terminal 85.

Is there 12V at socket #6 (highbeam, white wire) or socket #2 (lowbeam, black wire) on vehicle side?

Corresponding wire isopen in vehicle harness.Repair wire or replace

harness.

Corresponding wire isopen in plow harness.Repair wire or replace

harness.Attach a ground jumper wire to relayterminal 85 with black/orange wire. Isthere now 12V at relay terminal 87?

Replace headlamp relay.Do plow lights work?

Remove jumper wire from relay.Disconnect 9-pin connector. Attachground jumper wire to socket #5 on

vehicle side. Is there 12V at socket #6(high beam) or socket #2 (low beam)?

Black/orange ground wire inplow harness is open. Repair

wire or replace harness.

Reconnect 9-Pinconnector. Attach

ground jumper to (-)motor terminal. Do

plow lights come on?

Black/orangewire in plowharness is

open. Repairwire or replace

harness.

Poor groundbetween battery

and motor (-)terminal. Repair

vehicle or plow (-)battery cable.

Black/orange ground wire invehicle harness is open.Repair wire or replace

harness.Plow lights are good.

No. 21936 December 17, 2004

57

1. Verify plow park/turn (P/T) bulbsand contacts are good.

2. Turn parking lamps and ignitionon.


4. Refer to the Vehicle Harness 9- or12-Pin Connector diagram.

PARK/TURN LAMP TEST – 9-PIN OR 12-PIN HARNESS

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Disconnect 9 or 12-pin connector.Is there 12V at socket #11 on the

vehicle side?

Reconnect 9 or 12-pinconnector. Remove P/T bulbsfrom plow lights. Is there 12Vat each brown wire terminal in

the sockets?

Do vehicle park lampswork?

Poor ground connectionbetween bulb and socket orblack/orange ground wire is

open in plow harness. Repairwire or replace harness.

YESYESYES

NONO

Repair vehicle electricalsystem.

NOIs the optional Park/Turn Relay Kitinstalled? (Vehicle harness brown

wire connects to relay kit gray wire.)NO

Brown wire is open in plowharness. Repair wire or replace

harness.

YES

Purple or gray wire is open in plowharness. Repair wire or replace

harness.

Is the optional Park/Turn Relay Kitinstalled? (Vehicle harness graywire and purple wires connect torelay kit gray and purple wires.)

Poor connection to vehicle circuit oropen purple (right) or gray (left) wirein vehicle harness. Repair wire or

replace harness.

Poor connection to vehicle circuit oropen brown wire in vehicle harness.

Repair wire or replace vehicleharness. Go to Optional Park/Turn Relay Kit Test

Do vehicle turn signalswork?

Disconnect 9 or 12-pin connector. Isthere 12V at sockets #10 for right

turn and #9 for left turn?

Reconnect 9 or 12-pin connector.Remove P/T bulbs from plow

lights. Is there 12V at each redwire terminal in the sockets? (The

purple and gray wires are spliced tored wires in the P/T sockets.)

Poor ground connectionbetween bulb and socket orblack/orange ground wire is

open in plow harness. Repairwire or replace harness.

Repair vehicle electricalsystem.

Go to Optional Park/Turn Relay Kit Test

YES YES YES

NO

YES

NO

NONO

No. 21936 December 17, 2004

58

OPTIONAL PARK/TURN RELAY KIT TEST

1. Turn signal applications use bothgray and purple relay circuits.

2. Park lamp applications use grayrelay circuit only. If gray relaycircuit fails, purple relay circuitcan be used instead.

3. Refer to the Optional Park/TurnRelay Kit schematic.

4. Verify relay kit red and black wiresare connected to battery (+) and(–) respectively.

5. Verify in-line 10 amp fuse in redwire is good.

6. Disconnect long and short grayand purple wires to isolate relaycircuits.

Note: If the snowplow park/turnlamps are on when the vehicle park/turn lamps are off, replace the relaykit.

Apply 12V to long gray wire. Isthere 12V at short gray wire?

Apply 12V to long purple wire. Isthere 12V at short purple wire?

Relay kit is OK. Check bulletconnectors on vehicle

park/turn circuits.NO NO

YESYES

Gray relay circuit failed.Use good purple relay

circuit or replace relay kit.

Purple relay circuit failed.Replace relay kit.

No. 21936 December 17, 2004

59�3 1�23��>��3�8

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OPTIONAL PARK/TURN RELAY KIT SCHEMATICS

WIRED FOR PARK LAMPS WIRED FOR TURN SIGNALS

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No. 21936 December 17, 2004

60

VEHICLE HEADLAMP TEST – 12-PIN HARNESS – 3 RELAY SYSTEM ONLY

1. Verify correct harness and wireinstallation to headlamp relays,vehicle headlamps, and vehicleheadlamp connectors.


3. Disconnect all harnesses at thefront of the vehicle.

4. Turn vehicle headlamp switch on.For vehicles with Daytime

Running Lamps (DRL’s), turnignition on. DRL equipped vehicleshave a pink wire instead of abrown wire on relay terminal 86.

5. Verify power for both high and lowbeam and ground are present atthe original vehicle headlampconnectors.

6. Refer to the Electrical Schematic– 12-Pin Harness, and theHeadlamp Test Diagram – 12-PinHarness. The specific wiringdiagram for the vehicle can befound in the plow installationinstructions, the WESTERN®

UNIMOUNT® Service Manual Vol. 2.,or (for ’98 and older vehicles) themanual Headlamp ElectricalSchematics for Straight Blades.

* Repair wire or replace harness forall open or shorted wires.

YES

YES NONO

YES NO

Relays are activated.Black/orange wire invehicle harness isshorted to ground.

NO

*

Red wire in headlampharness is open.

Green wire in headlampharness is open.

Replace vehicle highbeam relay.

*Low beam: orange or yellowwire in headlamp harness is

open.

High beam: Is there 12V atterminal 30 with the green wireat the vehicle high beam relay?

Remove headlamp harnessconnectors from vehicle

headlamps. Is there 12V ateach orange wire socket (low

beam) and red wire socket(high beam)?

Remove black/orange wirefrom vehicle high beamrelay. Do the high beam

lights work?

Is there 12V at terminal87a with the red wire atthe vehicle high beam

relay?

**YES

No. 21936 December 17, 2004

61

VEHICLE HEADLAMP TEST – 12-PIN HARNESS – 3 RELAY SYSTEM ONLY


*

**

Check for poor orcorroded connections inthe headlamp harness

and at relays.

Is there ground at the Ltblue/white wire socket inthe right connector and

Dk blue/white wire socketin the left connector?

Right side headlamp: Attacha ground jumper wire toterminal 87a with the Dk

blue/white wire on the curbside relay. Does the

headlamp work?

Left side headlamp: Attach aground jumper wire to

terminal 87a with the Ltblue/white wire on the driver

side relay. Does theheadlamp work?

Right side headlamp: Attacha ground jumper wire toterminal 30 with the Dk

blue/white wire on the curbside relay. Does the

headlamp work?

Left side headlamp: Attach aground jumper wire toterminal 30 with the

Lt blue/white wire on thedriver side relay. Does the

headlamp work?

Relays are activated.Black/orange wire in

vehicle harness is shortedto ground.

Dk blue/white or Ltblue/white wire in

headlamp harness isopen.

Disconnect theblack/orange wire from

the relay. Does theheadlamp work?

Replace relay.

YES

YES

YES

NO

NO

NO

NO

YES

YES

YES

Dk blue/white or Ltblue/white wire in

headlamp harness isopen.

No. 21936 December 17, 2004

62

PLOW HEADLAMP TEST – 12-PIN HARNESS – 3 RELAY SYSTEM ONLY (’98 AND OLDER VEHICLES)

1. Verify correct harness and wireinstallation to headlamp relays,vehicle headlamps, and vehicleheadlamp connectors.



4. Turn vehicle headlamp switch on.For vehicles with DaytimeRunning Lamps (DRL’s), turnignition on. DRL equippedvehicles have a pink wire insteadof a brown wire on relay terminal 86.

5. Verify power for both high and lowbeam and ground are present atthe original vehicle headlampconnectors.

6. Refer to the Electrical Schematic– 12-Pin Harness, and theHeadlamp Test Diagram – 12-Pin

Harness. The specific wiringdiagram for the vehicle can befound in the plow installationinstructions, the WESTERN®

UNIMOUNT® Service Manual Vol. 2.,or (for ’98 and older vehicles) themanual Headlamp ElectricalSchematics for Straight Blades.

If no low beam: black wire inplow harness is open.

If no high beam: white wire isopen.

If no high or low beam: Dkblue/orange wire is open.

On the plow harnessconnector, attach a ground

jumper wire to pin #8 and 12Vto pin #2 (low beam) or pin #6(high beam). Does the rightside plow headlamp work for

both high and low beam?

On the vehicle 12-pinharness connector, is

there 12V at socket 6 (highbeam) and sockets 2 and

7 (low beam)?

Disconnect the 12-pinharness connector. Do

the vehicle headlights turnon?

NO*

YESYES

If no low beam: black/whitewire in plow harness is open.If no high beam: white wire is

open.If no high or low beam : Ltblue/orange wire is open

YESOn the plow 12-pin harnessconnector, attach a ground

jumper wire to pin #12 and 12Vto pin #7 (low beam) or pin #6(high beam). Does the left

side plow headlamp work forboth high and low beam?

Either black wire (rightheadlamp) or

black/white wire (leftheadlamp) in vehicle

harness is open.

White wire in vehicleharness is open.

NO

NO

Go to VehicleHeadlamp Test

12-pin.

Green wire inheadlamp harness is

open.

Yellow or orange wirein headlamp harness

is open.

NONO

NO YES

YES

High beam: Open theconnection between the white

wire of the vehicle harnessand the green wire of the

headlamp harness. Is there12V at the green wire?

Low beam: Open theconnection between the yellow

and orange or orange wireterminal of the headlamp

harness and the black wire ofthe vehicle harness. Is there12V at the yellow and orange

or orange wire?

*

*

*

*

YES

*


No. 21936 December 17, 2004

63

Brown or pink wire is open.Check brown wire connectionto vehicle park lamp circuit or

fuse in pink wire.

Dk blue wire in headlampharness open.

**

Dk blue/orangewire in vehicle

harness is open.

*Move ground jumper wire to

terminal 30 with Dk blue wire atcurb side relay. Does right

plow headlamp work?Remove ground jumpers. Isthere 12V at terminal 86 with

brown wire (pink wire forDRLs) at all relays?

Lt blue/orangewire in vehicle

harness is open.

*Move ground jumper wire toterminal 30 with Lt blue wire at

driver side relay. Does leftplow headlamp work?

Lt blue wire inheadlamp harness is

open.

*

Remove ground jumper wires.Disconnect the 12 pin harness

connector. Touch socket 5 of thevehicle harness connector with a

ground jumper wire. Do therelays make a clicking soundindicating they are activating?

Black/orangeground wire in

vehicle harness isopen.

Attach a ground jumper wire toterminal 85 with black/orangewire at the relays. Do plow

headlamps work?

*

Black/orangeground wire in

plow harness isopen.

*Replace relay.

Reconnect all harnessconnectors. Attach a ground

jumper wire to terminal 87 withthe Lt blue/orange wire at thedriver side relay. Does theright plow headlamp work?

Reconnect all harnessconnectors. Attach a ground

jumper wire to terminal 87 withthe Dk blue/orange wire at thecurb side relay. Does the left

plow headlamp work?

YES

YES

YES

NO

NONO

YES

NO

YES

YES

NO

NO

YES

NO

YES

PLOW HEADLAMP TEST – 12-PIN HARNESS – 3 RELAY SYSTEM ONLY (’98 AND OLDER VEHICLES)


No. 21936 December 17, 2004

64

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HEADLAMP TEST DIAGRAM – 12-PIN HARNESS – 3 RELAY SYSTEM ONLY (’98 AND OLDER VEHICLES)

NOTE: DRL applicationsrequire a DRL kit. DRL kitnot shown.

No. 21936 December 17, 2004

65

NOTES

No. 21936 December 17, 2004

66

NOTES

No. 21936 December 17, 2004

68

Copyright © 2004 Douglas Dynamics, L.L.C. All rights reserved. This material may not be reproduced or copied, in whole or in part, in any printed, mechanical, electronic, film or otherdistribution and storage media, without the written consent of Western Products. Authorization to photocopy items for internal or personal use by Western Products outlets orsnowplow owner is granted.

Western Products reserves the right under its product improvement policy to change construction or design details and furnish equipment when so altered without reference toillustrations or specifications used. Western Products and the vehicle manufacturer may require and/or recommend optional equipment for snow removal. Do not exceed vehicleratings with a snowplow. This product is manufactured under the following US patents: 4,999,935; 5,420,480; 5,806,213; 5,806,214; 6,253,470; RE35,700; CAN PATENT 2,060,425and other patents pending. Western Products offers a limited warranty for all snowplows and accessories. See separately printed page for this important information. The followingare registered (®) trademarks of Douglas Dynamics, L.L.C.: ISARMATIC®, PRO-PLOW®, UniMount®, WESTERN®

Printed in USA

WESTERN PRODUCTS7777 NORTH 73RD STREETP.O. BOX 23045MILWAUKEE, WISCONSIN 53223

A DIVISION OF DOUGLAS DYNAMICS, L.L.C.

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