Theory Of Operation

The Fog Lamp Switch is integral to the Headlamp Switch. When the Body Control Module (BCM) receives an input signal from the Headlamp Switch, requesting Fog Lamp illumination, the BCM provides a Pulse Width Modulated (PWM) voltage output through the Fog Lamp Control Circuit to the Fog Lamps. A ground path for the Fog Lamps is provided through the wiring harness to the body sheet metal.