GM Service Manual Online
For 1990-2009 cars only

Headlamp Washer System Components

The headlamp washer system consists of the following components:

    • Headlamp washer relay
    • Washer fluid level switch
    • Headlamp washer pump
    • HDLP WASH 30A circuit breaker

Headlamp Washer System Controls

The headlamp washer system is controlled by the following components:

    • Headlamp washer relay
    • Body control module (BCM)
    • Washer fluid level switch
    • Windshield wiper/washer switch

Headlamp Washer System Operation

Battery voltage is supplied to the headlamp washer relay switched input. The windshield washer pump control circuit is spliced to the headlamp washer relay. When the windshield washer switch is pressed, battery voltage is supplied on washer switch signal circuit to the headlamp washer relay which energizes the relay. This allows battery voltage from the headlamp washer relay switched input to relay switched output to supply voltage circuit of the headlamp washer pump. The windshield washer fluid level switch also provides a signal circuit to the headlamp washer relay and does not allow the relay to be energized when the fluid level is insufficient for pump operation. The body control module (BCM) controls the ground of the headlamp washer relay and the headlamps must be on for the relay to receive ground and operate. On the early production vehicles, the headlamp washers activate with each windshield washer cycle on the domestic vehicles and after every 3 windshield washer cycles on the exports. For later production vehicles, all headlamp washer systems activate after every 5  windshield washer cycles.