Theory Of Operation

The Body Control Module (BCM) receives an input from the Left Multi-function Switch requesting headlamp low beam and high beam illumination. For headlamp low beam illumination, the BCM provides a voltage output to the Headlamps through the Left and Right Low Beam Driver circuits. For headlamp high beam illumination, the BCM provides a ground output to the Headlamp Relay through the High Beam Headlamp Relay Control circuit. When the Headlamp Relay energizes, voltage is sent to the headlamps, through the High Beam Driver circuit, in order to illuminate the headlamp high beams. A ground path for the headlamps is present through the harness to the body sheet metal. For additional information on Headlamp operation. Refer to HEADLAMPS .