Theory Of Operation

The Radiator Fan Module is a smart device which is integrated into the Radiator Fan Assembly and receives the Pulse-Width Modulated (PWM) Radiator Fan speed signal from the Powertrain Control Module (PCM) to control fan speed. The Radiator Fan Module will control the fan speed based on this input. During normal operation, the voltage on the PWM Control circuit will be approximately 1.4 volts with the Radiator Fan connector plugged in and the fan is being commanded off by the PCM. As the Radiator Fan speed is being commanded higher the voltage will increase. With the Radiator Fan commanded at high speed the voltage will increase to approximately 8.0 volts.