Radiator Cooling Fan Control Module: Testing and Inspection

Fan control is accomplished three ways. The fan runs when the air conditioning pressure reaches a set psi see charts below. In addition to this control, the fan is turned on by the temperature of the coolant which is sensed by the coolant temperature sensor which sends the message to the Powertrain Control Module (PCM). The PCM turns on the fan through a fan relay. On models equipped with automatic transmission, a transmission fluid thermistor may have some influences on fan operation. See Wiring Diagrams for circuity and diagnostics provided.
The Powertrain Control Module (PCM) provides fan control for the following conditions:
^ The fan will not run during cranking until the engine starts no matter what the coolant temperature is.
^ Fan will run when the air conditioning clutch is engaged, low pressure cutout switch is closed and once set compressor head pressure is reached. See charts.
^ Fan will run according to the following information charts.





Radiator Fan Operation