Radiator Cooling Fan Control Module: Description and Operation

PWM FAN CONTROL MODULE 4.0L

DESCRIPTION
The Pulse Width Modulated (PWM) radiator cooling fan relay is located behind the front bumper fascia below the right headlamp.

OPERATION
The PWM relay is used to control the speed of the electric radiator cooling fan. It allows for multiple fan speeds. This allows for improved fan noise and A/C performance, better engine cooling, and additional vehicle power.
PWM relay operation is controlled by the Powertrain Control Module (PCM). To operate the PWM relay, the PCM looks at inputs from:
^ Engine coolant temperature
^ Ambient temperature from the body controller
^ Vehicle speed
^ Transmission oil temperature
^ A/C switch position (A/C request)