Radiator Cooling Fan: Description and Operation

Circuit Description
The engine control module (ECM) controls the operation of the radiator fan relay and the condenser fan relay. The control module monitors coolant temperature through the engine coolant temperature sensor. The module also monitors A/C operation through the A/C ON input and A/C pressure switch input. Using these inputs, the module will ground the coil of the appropriate relay to provide fan operation. In high speed mode, the module will ground the coil of the condenser fan relay and radiator fan relay.

Battery voltage will then provided to the condenser fan motor and radiator fan motor through each relay contact. The radiator fan motor and the condenser fan motor have their own ground (Radiator fan motor: G01, Condenser fan motor: G02). In low speed mode, the module will ground the coil of the radiator fan relay and battery voltage will then supplied to the radiator fan motor and condenser fan motor. In this case, the radiator fan motor and condenser fan motor have a common ground (G02).