Operation

OPERATION

The electric radiator cooling fan is controlled by the Powertrain Control Module (PCM) through the radiator cooling fan relays. The PCM regulates fan operation based on input from the engine coolant temperature sensor, battery temperature sensor, air conditioning select switch and vehicle speed.


The fan is not energized during engine cranking regardless of the electrical input from the temperature sensors and air conditioning switch. However, if engine operation conditions warrant fan engagement, the fan will run once engine starts.


On vehicles NOT equipped with AC: The relay is energized when the coolant temperature is above 80� C (176� F), or battery temperature sensor above -12� C (10� F). It will then de-energize when coolant temperature drops below 82� C (180� F), or battery temperature sensor below -9� C (16� F).


Vehicles Equipped with AC: In addition to using coolant temperature and battery temperature sensor to control cooling fan operation, the cooling fan will also be engaged when the ,air conditioning system is activated. The relay is also energized when air conditioning is selected and coolant temperature is above 95� C (203� F), or, air conditioning is selected and battery temperature sensor is above 41� C (106� F). It will then de-energize when air conditioning is selected and coolant temperature is below 92� C (198� F), or air conditioning is selected and battery temperature is below 38� C (100� F).