Engine Cooling Fan System

Circuit Description
The Electric Cooling Fan(s) are controlled by the Body Control Module (BCM) which enables the fans through the PCM. The PCM enables the ground path for the three cooling fan relays. The relay(s) are used to control the high current flow to power the cooling fan motors. When minimum cooling is required, the BCM will command the PCM to energize cooling fan relay #1 and since both fans are connected in series through the Mode Control relay, both fans will operate at low speed. When maximum cooling is required, the BCM will communicate to the PCM to energize all three cooling fan relays. Power is supplied to the left fan through the Mode Control relay. The right fan is powered directly through cooling fan relay #2 causing both fans to operate at high speed.

For diagnostic information see Electric Cooling Fan Diagnosis under Computers and Control Systems. Component Tests and General Diagnostics