Radiator Cooling Fan Motor: Description and Operation

Radiator fan control is accomplished in two ways. A pressure transducer on the compressor discharge line sends a signal to the powertrain control module (PCM) which will activate the fans. The fans are also turned on by a coolant temperature sensor, which sends a message to the engine controller. The engine controller then sends a signal to the fan relay which in turn switches the coolant fans on.

Fan Operating Mode Conditions.:

Switching through the engine controller provides fan control for the following conditions:
1. Fans will not run during cranking until engine starts, no matter what coolant temperature is.
2. Fan runs according to chart shown.