2.2 Cooling Fans - Just Commodores

Engine Cooling – GEN III V8 Page 6B3–7

Page 6B3–7

2.2 Cooling Fans

Overview All GEN III V8 vehicles are fitted with a high power cooling fan system consisting of two dual-speed fans, which operate with a two-stage strategy as follows:

• Stage 1 – both fans operate at low speed.

• Stage 2 – both fans operate at high speed.

There are two systems applicable. Refer the table below:

Fan Module Capacity Application

400W Sedan, Utility, Wagon, Coupe

430W 2WD Regular and Crew CabAWD Wagon, Regular and

Crew Cab

Relays

The engine cooling fan relays are located in the fuse and relay compartment under the hood.

Legend – 400W System

1 Cooling Fan Relay 1 for low-speed fan operation. 2 Cooling Fan Relay 2 (in conjunction with Cooling Fan

Relay 1) for high-speed fan operation.

Legend – 430W System

1 Cooling Fan Relay 2 (in conjunction with Cooling Fan Relays 1 and 3) for high-speed fan operation.

2 Cooling Fan Relay 1 for low-speed fan operation. 3 Cooling Fan Relay 3 (in conjunction with Cooling Fan

Relays 1 and 2) for high-speed fan operation.

Figure 6B3 – 2


Page 6B3–8

Fan Motors

Figure 6B3 – 3

Legend

1 Three-wire Harness 2 Armature Shaft 3 Drain Hole

Dimension applicable to small diameter fan blade Dimension applicable to large diameter fan blade

All fan motors are 12 Volt, dual-speed types. Accordingly, the internal construction of the fan motor consists of four brushes and four permanent magnets. A three-wire pigtail harness is permanently attached to both motors and is attached to the polypropylene fan shroud at two locations by integral clips moulded as part of the shroud. The RHS motor harness is connected directly to the engine harness through a 6-pin connector. It also carries an additional 4-pin connector that attaches to the LHS motor harness and enables individual removal of the LHS and RHS fan and motor assemblies when necessary, refer to Figure 6B3 – 1. The two associated electrical connectors are attached to the shroud by way of slide lock clips. The motor is attached to the polypropylene fan shroud by three bolts installed at the threaded mounting flanges, which protrude symmetrically from the rear of the fan motor housing, refer to Figure 6B3 – 3.

Suppression capacitors located at the fan motor brush holders are incorporated. These suppression capacitors help eliminate fan motor noise through the radio speakers. As these capacitors are not serviced separately, the motor assembly must be replaced should a problem occur with either capacitor.

The enclosed fan motor housing is constructed of yellow zinc coated steel. A drain hole is located in the bottom of the housing to allow for breathing and draining of any moisture ingress.

Both fan motors rotate in an anticlockwise direction when viewed from the fan motor side.

Both LHS and RHS fan and motor are balanced as a unit and fan blades must not be separated from their respective motors. Fan motors and blades are serviced only as an assembled unit. However, it should be noted that the central nut attaching the fan blade to the motor shaft has a left-hand thread.


Page 6B3–9

400W Cooling System The cooling system includes two, dual-speed, engine cooling fan motors, both of which, drive fans with five, asymmetrical blades that are designed to reduce air noise. The larger, right fan is 354 mm in diameter and has a motor rated at 220 Watts, while the smaller, left fan is 293 mm in diameter with a motor power rating of 180 Watts.

The following outlines the operation of the cooling system, at block level, also showing what inputs the Powertrain Control Module (PCM) requires.

Figure 6B3 – 4

With 12 volts applied and the fans mounted to the radiator with a condenser fitted, the operating speeds are:

Stage 1 Stage 2

Large Fan 2,350 ± 150 rpm 2,750 ± 150 rpm

Small Fan 2,050 ± 150 rpm 2,300 ± 150 rpm


Page 6B3–10

Figure 6B3 – 5

Legend

1 Fan Shroud 2 Radiator Drain Tap 3 Radiator 4 Fan Shroud Lower Support 5 Fan Shroud Upper Support / Locking Retainer 6 Small, Left Fan – 5 Blade, 293 mm Diameter 7 Small, Left Fan Motor – 180 Watt, Dual-speed

8 Left Fan Motor Harness Connector (3 terminal) 9 Left and Right Fan Motor Harness Connector (5 terminal) 10 Oil Cooler, Upper Line Connection (Auto. Trans. only) 11 Oil Cooler, Lower Line Connection (Auto. Trans. only) 12 Large, Right Fan – 5 Blade, 354 mm Diameter 13 Large, Right Fan Motor – 220 Watt, Dual-speed

Operation

The electrical circuitry for each of the cooling fans has two negative and one positive terminal to achieve the dual-speed requirement. In addition, the current draw is directed through separate negative terminals at the joint connector (9) in Figure 6B3 – 5 for each fan motor to reduce the heat burden on the electrical connectors. Figure 6B3 – 6 shows how current flows through one negative motor terminal of each fan at low operating speed. Current flows through both negative terminals of each fan motor when operating at high speed.

The positive terminals are permanently connected to battery voltage, via fusible links F101 (large fan) and F107 (small fan).

Stage 1 Fan Operation

The PCM determines when to enable Stage 1, based on inputs from the A/C request signal, Engine Coolant Temperature (ECT) sensor and the Vehicle Speed Sensor (VSS).

When the PCM determines that Stage 1 cooling fan operation is required it energises Engine Cooling Fan Relay 1 (R7) by suppling a ground signal on circuit 335 causing the relay to operate. Once Engine Cooling Fan Relay 1 is operated it provides a ground for the fan motors low-speed negative terminals via circuit 532. The engine cooling fans then operate at low speed (Stage 1).


Page 6B3–11

Figure 6B3 – 6


Page 6B3–12

Figure 6B3 – 7

Conditions for Stage 1 Fan Operation

1 The PCM switches ON Engine Cool Fan Relay 1 (R7) when the following conditions have been met:

• Air conditioning request indicated (YES) and the vehicle speed is less than 30 km/h, or

• Air conditioning pressure is greater than 1,500 kPa, or

• Coolant temperature is greater than 108° C, or

• When a ECT sensor failure in conjunction with an Intake Air Temperature (IAT) sensor failure is detected by the PCM. For additional information. Refer to Section 6C3-2 Powertrain Management – GEN III V8 – Diagnostics, or

• When the ignition switch is turned from on to off and the engine coolant temperature is above 113° C, the PCM will continue to energise Engine Cool Fan Relay 1 for four minutes.


Page 6B3–13

2 The PCM switches OFF Engine Cool Fan Relay 1 when the following conditions have been met:

• Air conditioning request not indicated (NO) and the coolant temperature is less than 104° C, or

• Air conditioning request indicated (YES) with pressure less than 1,170 kPa, vehicle speed greater than 50 km/h, and coolant temperature less than 108° C.

N O T E The Stage 1 cooling fan operation has a minimum run on time function of 30 seconds.


When the PCM determines that Stage 2 cooling fan operation is required. Figure 6B3 – 8 shows how the PCM energises Engine Cooling Fan Relay 2 (R5) by suppling a ground signal on circuit 473 causing the relay to operate. Once Engine Cooling Fan Relay 2 has operated, it provides a ground for the fan motors high-speed negative terminals (internally connected to the second negative brush of each fan motor) via circuit 409. As the low-speed negative terminals are still grounded through Engine Cooling Fan Relay 1 (R7), the engine cooling fans will operate at high speed (Stage 2).

Figure 6B3 – 8


Page 6B3–14

Figure 6B3 – 9


1 The Engine Cool Fan Relay 2 cooling fan relay will be turned ON if the Engine Cool Fan Relay 1 has been energised for 1 second and the following conditions have been met:

• Engine coolant temperature is above 113° C, or

• Air conditioning pressure is greater than 2,400 kPa.

N O T E If the Stage 1 cooling fan function is off when the criteria for turning on the Stage 2 cooling fan function are first met, the Stage 2 cooling fan function will begin to operate 1 second after the Stage 1 cooling fan function is switched on.


Page 6B3–15

2 The PCM will turn the high-speed cooling fan function OFF when:

• The engine coolant temperature is less than 108.5° C, and

• Air conditioning request is not indicated (NO), or

• Air conditioning request is indicated (YES) and the pressure is less than 1,900 kPa.

N O T E • The Stage 2 cooling fan operation has a

minimum run on time function of 30 seconds after the ignition switch has been turned Off.

• The PCM determines operation of the two dual-speed engine-cooling fans based on A/C request, A/C system pressure (where fitted), engine coolant temperature and vehicle speed signal inputs. For further details of the engine cooling fan operation and diagnosis of the system. Refer to Section 6C3-2 Powertrain Management – GEN III V8 – Diagnostics.

430W Cooling System The cooling system for the GEN III V8 engine includes two, dual-speed, engine cooling fan motors, both of which, drive fans with five, asymmetrical blades that are designed to reduce air noise. The larger, right fan is 354 mm in diameter and has a motor rated at 215 Watts, while the smaller, left fan is 293 mm in diameter with a motor power rating of 215 Watts also.

The following diagram outlines the operation of the cooling system, at block level, also showing what inputs the Powertrain Control Module (PCM) requires.

Figure 6B3 – 10

With 12 volts applied and the fans mounted to the radiator with a condenser fitted, the operating speeds are:

Stage 1 Stage 2

Large Fan 1,200 ± 150 rpm 2,400 ± 150 rpm

Small Fan 1,700 ± 150 rpm 3,000 ± 150 rpm


Page 6B3–16

Figure 6B3 – 11

Legend

1 Fan Shroud 2 Radiator Drain Tap 3 Radiator 4 Fan Shroud Lower Support 5 Fan Shroud Upper Support / Locking Retainer 6 Small, Left Fan – 5 Blade, 293 mm Diameter 7 Small, Left Fan Motor – 215 Watt, Dual-speed

8 Left Fan Motor Harness Connector (3 terminal) 9 Left and Right Fan Motor Harness Connector (5 terminal) 10 Oil Cooler, Upper Line Connection (Auto. Trans. only) 11 Oil Cooler, Lower Line Connection (Auto. Trans. only) 12 Large, Right Fan – 5 Blade, 354 mm Diameter 13 Large, Right Fan Motor – 215 Watt, Dual-speed

Operation

The cooling fans operate in two stages in which both stages both fans run. In Stage 1 the two fan motors are connected in series so that both fans run at low speed. In Stage 2 each fan motor is connected to battery supply in parallel so that both fans run at high speed.

The positive terminals of the cooling fans are permanently connected to battery voltage via fusible links F101 (both fans at Stage 1 and large fan at Stage 2) and F107 (small fan at Stage 2).


The Powertrain Control Module (PCM) determines when to enable Stage 1 (i.e. Engine Cooling Fan Relay 1 is energised and both fans, being connected in series, run at low speed) based on inputs from the A/C request signal, Engine Coolant Temperature (ECT) sensor and the Vehicle Speed Sensor (VSS).

Figure 6B3 – 12 shows when the conditions for Stage 1 operation are met, the PCM provides a ground to the coil of Engine Cooling Fan Relay 1 (R5), causing it to operate (turn ON); the fan current path is then from the battery via fusible link F101, through the large fan motor, the de-energised contacts of Engine Cooling Fan Relay 2 (R7), the small fan motor and Engine Cooling Fan Relay 1 (R5) to ground.


Page 6B3–17

Figure 6B3 – 12


Page 6B3–18

Figure 6B3 – 13


1 The Engine Cooling Fan Relay 1 (R5) will be turned ON when the A/C request indicated (YES) and either:

• The vehicle speed is less than 30 km/h; or

• A/C pressure is greater than 1,500 kPa; or

• The coolant temperature is greater than 98° C; or

• If the coolant temperature is greater than 113° C, when the ignition is switched off, the relay is energised for approximately four minutes, this is known as Low Fan Run On; or

• If an ECT sensor fault is detected and a DTC such as DTC P0117, P0118, P1114 or P1115 is set.

2 The Engine Cooling Fan Relay 1 will be turned OFF when any of the following conditions have been met:

• An A/C request is not indicated (NO) and the coolant temperature is less than 95° C; or

• An A/C request is indicated (YES) and the vehicle speed is greater than 50 km/h and A/C pressure is less than 1,170 kPa and the coolant temperature is less than 98° C.


Page 6B3–19


Figure 6B3 – 14


Page 6B3–20

Figure 6B3 – 15

The PCM also determines when the engine cooling fans should operate at Stage 2. Figure 6B3 – 14 shows how Engine Cooling Fan Relays 1, 2 and 3 are energised and both fans, each being connected to battery supply, run at high speed based on inputs from the A/C request signal, VSS and the ECT sensor. When the conditions for Stage 2 operation are met, the PCM provides (in addition to that already provided for the coil of Engine Cooling Fan Relay 1) a ground to the coils of Engine Cooling Fan Relays 2 and 3 (R7 and R6), causing them to operate (turn ON). For the large fan the current path is from the battery via fusible link F101, through the large fan motor and Engine Cooling Fan Relay 2 (R7) to ground. For the small fan, the current path is from the battery via fusible link F107, through Engine Cooling Fan Relay 3 (R6), through the small fan motor and Engine Cooling Fan Relay 1 (R5) to ground.


Page 6B3–21


1 The Engine Cooling Fan Relay 2 (R7) is controlled by the PCM. The PCM will only activate Stage 2 fan operation, if the Engine Cooling Fan Relay 1 (R5) has been ON for two seconds and the following conditions are satisfied:

• An ECT sensor fault is detected and a DTC such as DTC P0117, P0118, P1114 or P1115 is set.

• Coolant temperature is greater than 108°C.

• The A/C refrigerant pressure is greater than 2400 kPa.

2 If the Engine Cooling Fan Relay 1 was OFF when the criteria was met to activate Engine Cooling Fan Relay 2, Stage 2 fan operation will occur 5 seconds after the Engine Cooling Fan Relay 1 is turned ON. If both engine cooling fan relays are ON, the PCM will turn OFF Engine Cooling Fan Relay 2 when:

• The engine coolant temperature is less than 102°C.

• A/C request not indicated (NO).

• A/C request indicated (YES) and A/C pressure is less than 1900 kPa.

N O T E • Both cooling fans will be turned off if the

vehicle speed is greater than 104 km/h. • The PCM determines operation of the two

dual-speed engine-cooling fans based on A/C request, A/C system pressure (where fitted), engine coolant temperature and vehicle speed signal inputs. For further details of the engine cooling fan operation and diagnosis of the system. Refer to Section 6C3-2 Powertrain Management – GEN III V8 – Diagnostics.

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2.2 Cooling Fans - Just Commodores