Radiator Cooling Fan Motor: Description and Operation

Electric Cooling Fan.:

The electric cooling fan is controlled by a thermo sensor, radiator fan relay and an engine coolant temperature switch. When coolant temperature reaches approximately 185°F, the thermo sensor contacts close, providing a ground circuit to the fan relay, which provides voltage to the fan motor. When coolant temperature drops to approximately 171°F, the thermo sensor contacts open, opening the fan relay and shutting off the cooling fan.