Caprice Wagon V8-350 5.7L (1994)
Radiator Cooling Fan Motor Relay: Description and Operation
Secondary Cooling Fan Relay
Cooling Fan Relay Circuit.
Purpose:
The PCM controls the ground path for the cooling fan relay and is used to control the high current flow to power fan motor. The PCM determines
operation based on various sensor inputs.
Operation:
The PCM will activate the secondary cooling fan when any of the following conditions exist at idle:
^ Certain PCM diagnostic trouble codes are set
^ Coolant temp is above 111°C (232°F)
^ A/C head pressure is above 240 psi
When 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 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 210 psi. The minimum run time for the secondary cooling fan is 26 seconds.
Location:
The secondary cooling fan relay is located in the underhood electrical center.
