Radiator Cooling Fan Motor: Description and Operation
DESCRIPTIONWhen the ignition switch is in either the Run or Start positions, system voltage is applied to the coils of the main engine relay and to fan relay 1. Because the main relay is grounded at G108, the relay is energized, its contacts close, and battery voltage is applied through the relay and the radiator fan fusible link to the contacts of fan relay 1.
OPERATION
When engine coolant temperature is below 194°F, the cooling fan temperature switch provides a ground for relay 1, the relay energizes and its contacts are pulled open.
Whenever engine coolant temperature reaches or exceeds 194°F, the cooling fan temperature switch opens, fan relay 1 is de-energized, its contacts close, and system voltage is applied through the relay to the cooling fan motor. Since the fan motor is grounded at G108, it start to operate as soon as voltage is applied.
When engine coolant temperature drops below 194°F, the cooling fan temperature switch closes to ground, fan relay 1 is energized the relay contacts are pulled open and system voltage is no longer applied to the fan motor.