Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit/System Description
The body control module (BCM) controls the windshield washer based on an input from the windshield washer switch, which is part of the windshield wiper/washer switch. The BCM monitors the windshield washer switch through a discrete signal circuit. When the washer switch is pressed, the signal circuit is pulled to ground. The BCM will respond by commanding the washer function.
The windshield washer uses a single windshield washer pump to provide fluid for both the front and rear washers. Changing the polarity of the motor will cause it to spin in opposite directions, feeding fluid to the front or rear. 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.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.