Rear Washer System

On vehicles equipped with a Rear Washer, the rear washer system consists of the rear window washer pump/relay and the rear washer switch which is located at the windshield wiper/washer switch. When the rear switch is pressed, the Body Control Module detects that the request from the rear wiper/washer switch, the BCM sends a request to the rear window washer pump relay and supplies Battery to the coil of the Rear Washer Pump Relay. This energizes the Relay, which provides voltage to the rear window washer pump. The window washer pump provides the washer fluids, and the rear wiper is activated.

Fig 1: Rear Wash System Block Diagram

Courtesy of GENERAL MOTORS COMPANY