Engine Cooling Fan Control

The ECM has a hardwired connection with the cooling fan control module. The ECM outputs a PWM signal to the fan control module which relates to the required fan speed. The fan speed is determined by factors such as engine coolant temperature and A/C operation. The fan control module reacts to the received signal by controlling the operating voltage of the fan motors. The fan control module confirms the fan speed operation on the same connection back to the ECM.