Circuit/System Description

WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.

The windshield washer pump is controlled by the body control module (BCM) via a printed circuit board (PCB) relay. The BCM monitors the front windshield wiper/washer switch signal circuit and when front washer activation is requested, the BCM applies voltage through the window washer pump relay control circuit. With the relay energized, fused battery voltage is applied through the switch contacts the relay and the windshield washer pump control circuit to activate the windshield washer pump in one direction to apply fluid to the front windshield.

When front washers are requested, the BCM applies voltage to the windshield washer pump relay control circuit. This causes the contacts in the windshield washer pump relay to close and supplies voltage to the windshield washer pump. Ground for the windshield washer pump is provided through the rear window washer pump relay, which is switched to ground in it's at-rest state.