Radiator Fan Relay

Using information supplied by A/C signal, ECT sensor, transmission thermoswitch (A/T) and TP sensor, PCM controls operation of electric cooling fan. PCM operates fan through radiator fan relay by grounding relay circuit. PCM regulates engine idle speed through IAC motor when fan is on.

On some models, a low speed fan relay and a high speed fan relay are used. On models using multiple fan relays, one relay operates under normal (low speed) operation and other relay works under high speed or extra load (A/C on) condition.

Some models use more than one cooling fan. Second fan may function as an auxiliary cooling device when A/C is engaged or during periods of engine overheating, or high A/C refrigerant pressure.