4.3L VIN [W] & 5.7L VIN [P] ONLY
Several descriptions of the cooling system and fans are listed first, following by the operation of the cooling fans.
Description: Overview
The 4.3L VIN [W] & 5.7L VIN [P] engines each have the same three different cooling system options available
- Base cooling system
- Extra-capacity cooling system ("V03")
- Heavy-duty cooling system ("V08")
Each system has a different cooling fan arrangement. See 4.3L VIN [W] & 5.7L VIN [P] COOLING FAN OPTIONS table for a summary of all the fan configurations. (Scheme 1)for a view of the different fan configuration.
The following text provides a high-level overview of each type of available cooling system.
Description: Base Cooling System
The base version consists of an aluminum core with plastic end tanks radiator, a pressurized coolant recovery reservoir, an engine water pump driven by the camshaft gear (not by the drive belt), thermostat, and two-electric motor-driven fans. The right-hand end tank of the radiator contains a transmission oil cooler.
Description: Extra-Capacity Cooling System
The extra-capacity cooling system ("V03") has the same components except that the left-hand electric motor-driven fan has a larger size motor and the left-hand end tank of the radiator is larger to allow for an engine oil cooler provided within that end tank.
Description: Heavy-Duty Cooling System
The heavy-duty cooling system ("V08") has the same components as the extra-capacity cooling system except that the right-hand electric motor-driven cooling fan is replaced by a belt-driven hydraulic clutch-controlled fan. The coolant hoses connecting the engine to the radiator on the heavy duty cooling system have metal sections for protection from the belt-driven fan blades.
Operation: Overview
The electric cooling fan(s) are controlled by the PCM. The PCM controls the ground path for the cooling fan relay(s).
The relay(s) are used to control the high current flow to power the cooling fan motors. The PCM determines operation of the independent fans base on various sensor inputs.
Operation: Primary Cooling Fan
The primary cooling fan is controlled by the PCM based on inputs from the A/C system, Engine Coolant Temperature (ECT) sensor, Vehicle Speed Sensor (VSS).
The PCM will turn the primary cooling fan ON when any of the following conditions exist at idle
- Certain PCM Diagnostic Trouble Codes (DTCs) set.
- ECT above 225°F (107°C)
- A/C head pressure above 189 PSI.
Once the primary fan has been turned ON by the Engine Coolant Temperature (ECT) sensor, the PCM will turn the fan OFF when that temperature has dropped about 7°F (4°C). If the primary cooling fan has been turned ON by high A/C head pressure, the PCM will turn the fan OFF when the pressure has dropped to 150 PSI. The minimum ON time for the primary cooling fan is 50 seconds.
Operation: Secondary Cooling Fan
The secondary cooling fan is controlled by the PCM based on inputs from the A/C system, Engine Coolant Temperature (ECT) sensor, Vehicle Speed Sensor (VSS).
The PCM will turn the secondary cooling fan ON when any of the following conditions exist at idle
- Certain PCM Diagnostic Trouble Codes (DTCs) set.
- ECT above 232°F (111°C)
- A/C head pressure above 240 PSI.
Once the secondary fan has been turned ON by the Engine Coolant Temperature (ECT) sensor, the PCM will turn the fan OFF when that temperature has dropped about 7°F (4°C). If the primary cooling fan has been turned ON by high A/C head pressure, the PCM will turn the fan OFF when the pressure has dropped to 210 PSI. The minimum ON time for the primary cooling fan is 26 seconds.
Note. Vehicles equipped with the heavy-duty cooling system ("V08"), will have one mechanical fan (primary) and one electric fan (secondary).
| Coolant System | Left-Hand Fan | Right-Hand Fan |
|---|---|---|
| Base | Electric 100 Watt Motor | Electric 150 Watt Motor |
| Extra Capacity (V03) | Electric 240 Watt Motor | Electric 150 Watt Motor |
| Heavy-Duty (V08) | Electric 240 Watt Motor | Mechanical Belt-Driven |
| (1) (Scheme 1)for a view of the different cooling fan options. | ||
| (1) | (Scheme 1)for a view of the different cooling fan options. |
4.3L VIN [W] & 5.7L VIN [P] COOLING FAN OPTIONS (1)
Scheme 1
FOR ALL EXCEPT 4.3L VIN [W] & 5.7L VIN [P]
All FWD and some RWD vehicles use an electric cooling fan. See the ELECTRIC COOLING FAN APPLICATION table in the WIRING DIAGRAM section of this article for application information.
The cooling fan is used for radiator and A/C condenser cooling, and operates when A/C is on and/or when engine coolant exceeds a predetermined temperature. Electronic Control Module (ECM) or Powertrain Control Module (PCM) completes ground path for the cooling fan relay circuit. Relay contacts close and complete circuit between fusible link and fan motor.
To check for proper functioning of the cooling fans, proceed to the C-12 Chart: SYSTEM/COMPONENT TESTS - 5.7L . This chart will also lead you through any diagnosis necessary to troubleshoot faults found with the system.
Electric cooling fan TROUBLESHOOTING and TESTING procedures require entering self-diagnostics. For information on entering self-diagnostics, see information in appropriate SYSTEM/COMPONENT TESTS article in ENGINE PERFORMANCE.
Also, refer to the C-12 chart. This chart should be found in the SYSTEM/COMPONENT TESTS article, under the DIAGNOSTIC CHARTS header.
WIRING DIAGRAMS
| Application | Engine |
|---|---|
| "A" Body | 2.2L & 3.1L |
| "B" Body | 4.3L & 5.7L |
| "C" Body | 3.8L |
| "F" Body | 3.4L & 5.7L |
| "H" Body | 3.8L |
| "J" Body | 2.0L, 2.2L & 3.1L |
| "L" Body | 2.2L, 2.3L & 3.1L |
| "N" Body | 2.3L |
| "W" Body | 2.2L, 3.1L, 3.4L & 3.8L |
| "Y" Body | 5.7L |
ELECTRIC COOLING FAN APPLICATION
