Engine Cooling Fan: Operation

Electric cooling fan is controlled by a coolant temperature switch, cooling fan diode assembly and cooling fan relay. When coolant temperature reaches 188°F (87°C), coolant temperature switch contacts close and supply voltage to the cooling fan relay. Cooling fan relay contacts are then closed, turning on cooling fan. On A/C-equipped vehicles, the A/C clutch relay energizes cooling fan relay and operates the cooling fan when A/C clutch is energized.