Radiator Cooling Fan Motor Relay: Description and Operation

Two high and one low speed fan relays are used on this system. The ECM/PCM controls the engine coolant fan relay under several operating conditions. If the coolant temperature sensor indicates high engine temperature, the ECM/PCM will energize the relay to turn "ON" the fan. If the A/C is engaged, the ECM/PCM will turn the coolant fan on to cool the condenser as well as the radiator. Some fault codes will cause the ECM/PCM to turn "ON" the fan. Above certain vehicle speeds, the ECM/PCM will de-energize the fan relay since at higher road speeds there is ample air flow.