Caprice Wagon V8-350 5.7L (1994)
Radiator Cooling Fan Motor Relay: Description and Operation
Primary Cooling Fan Relay
Cooling Fan Relay Circuit.
NOTE: Vehicles with heavy duty cooling option VO8, utilize a mechanical primary fan.
Purpose:
The PCM controls the ground path for the cooling fan relay and determines operation based on various sensor inputs.
Operation:
The PCM will activate the primary cooling fan when any of the following conditions exist:
^ Certain PCM diagnostic trouble codes are set
^ Coolant temp is above 107°C (225°F)
^ A/C head pressure is above 189 psi
When 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 4°C (7°F). If the fan was 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 run time for the primary cooling fan is 50 seconds.
Location:
The primary cooling fan relay is located in the underhood electrical center.
