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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
4
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
5
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
6
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
7
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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No. 21936 December 17, 2004
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ISARMATIC® HYDRAULIC UNIT VALVE IDENTIFICATION AND LOCATION
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No. 21936 December 17, 2004
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VEHICLE HARNESS AND VEHICLE CABLE LOCATION
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No. 21936 December 17, 2004
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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
12
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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
13
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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
14
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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ELECTRICAL SCHEMATIC – 9-PIN HARNESS (’98 AND OLDER VEHICLES)
NOTE: DRL kit not shown.
No. 21936 December 17, 2004
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ELECTRICAL SCHEMATIC – 12-PIN HARNESS (’98 AND OLDER VEHICLES)
NOTE: DRL kit shown.
No. 21936 December 17, 2004
17
HYDRAULIC SCHEMATIC
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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
19
ANGLE RIGHT – HYDRAULIC
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No. 21936 December 17, 2004
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ANGLE LEFT – ELECTRICAL
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Blade Movement: Angle Left
Controller: Left
System Response:
1) By moving control lever orpressing the controller button, thecircuit board within the cab
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.
control supplies power for theelectrical circuit.
2) Electrical current flows throughthe motor relay, activating thepump motor, and solenoidcartridge valves S2 & S3, shiftingboth spools.
No. 21936 December 17, 2004
21
ANGLE LEFT – HYDRAULIC
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No. 21936 December 17, 2004
22
RAISE – ELECTRICAL
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Controller: Raise
System Response:
1) By moving control lever orpressing the controller button, thecircuit board within the cab
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
23
RAISE – HYDRAULIC
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No. 21936 December 17, 2004
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Blade Movement: Lower / Float
Controller: Lower
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 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
25
LOWER – HYDRAULIC
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No. 21936 December 17, 2004
26
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
27
STRIKING AN OBJECT WHILE PLOWING – RIGHT HYDRAULIC CYLINDER RETRACTS
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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
29
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HEADLAMPS – PLOW NOT CONNNECTED – 9-PIN (’98 AND OLDER VEHICLES)
NOTE: DRL kit not shown.
No. 21936 December 17, 2004
30
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NOTE: DRL kit shown.
No. 21936 December 17, 2004
31
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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.
Malfunctioning controller. Go to Control Test.
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
GENERAL DIAGNOSTIC TABLE
CONDITION POSSIBLE CAUSE ACTION
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.
Malfunctioning controller. Go to Control 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.
Malfunctioning controller. Go to Control Test.
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.
Hydraulic system malfunction. Go to Hydraulic System Test.
Malfunctioning controller. Go to Control 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.
Malfunctioning controller. Go to Control 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.
Hydraulic system malfunction. Go to Hydraulic System Test.
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.
Hydraulic system malfunction. Go to Hydraulic System Test.
Malfunctioning Controller. Go to Control Test.
No. 21936 December 17, 2004
38
GENERAL DIAGNOSTIC TABLE
CONDITION POSSIBLE CAUSE ACTION
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.
Malfunctioning controller. Go to Control Test.
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
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** 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
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.
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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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
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.
2. All bulbs must be good.
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.
3. Connect all harnesses at the frontof the vehicle.
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
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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.
2. All bulbs must be good.
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
* Repair wire or replace harness forall open or shorted wires.
*
**
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.
2. All bulbs must be good.
3. Connect all harnesses at the frontof the vehicle.
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
*
* Repair wire or replace harness forall open or shorted wires.
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)
* Repair wire or replace harness forall open or shorted wires.
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.