Radiator Cooling Fan Control Module: Description and Operation

CIRCUIT OPERATION
The radiator fan system uses two relays located in the Power Distribution Center (PDC). One relay is used for LOW speed fan operation and the other is for HIGH speed operation. The Powertrain Control Module (PCM) controls the operation of the relays depending on engine coolant temperature or A/C operation.

Power for the coil side of both relays is provided on circuit F18. This circuit is protected by a 10 Amp fuse located in cavity 9 of the Power Distribution Center (PDC). Power for the contact side of the relays is provided on circuit A16. This circuit is protected by a 40 Amp fuse located in cavity 17 of the PDC.

When LOW speed fan operation is required the PCM grounds circuit C24. This causes the contacts in the relay to CLOSE connecting circuits A16 and C23. Circuit C23 connects from the relay to the low speed portion of the fan motor. Ground for the motor is provided on circuit Z1, which terminates at the left strut tower.

When HIGH speed fan operation is required the PCM grounds circuit C27. This causes the contacts in the relay to CLOSE connecting circuits A16 and C25.

Circuit C25 connects from the relay to the high speed portion of the fan motor. Ground for the motor is provided on circuit Z1, which terminates at the left strut tower.