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.
Description & Operation
Rear window wiper and washer system consists of 2 motors, a transmission mechanism, circuit breaker, park switch and impeller pump. The wiper motor is a single-speed, permanent magnet type enclosed with a drive gear in a staked metal housing.
The transmission mechanism is contained in a plastic housing attached to the motor and gearbox assembly. The motor is protected by an internal, automatic reset type circuit breaker. The park switch, which is snapped into the side of the transmission housing, allows the wiper blade to stop in the park position when the wiper is turned off.
The washer motor is also permanent magnet type and is jar- mounted with the impeller type pump assembly on all except Camaro and Firebird, which use a flex vane type pump.
The wiper can only be operated with the ignition switch in the "RUN" or "ACC" position. There are 4 terminals on the motor and gearbox assembly. Terminals 1 and 2 are for the park switch and 3 and 4 are for the motor. See Fig 1 .
Turning the dash switch to "ON" position provides 12 volts to motor terminal 3. The circuit is completed to ground through motor terminal 4, thus operating the wiper motor. See Figure . Turning the switch to the "OFF" position provides 12 volts to motor terminal 3 through the park switch.
The wiper will continue to operate until a cam, located in the transmission housing, opens the park switch contacts. The cam opens the park switch contacts when the wiper blade reaches the correct park position. Pushing the wash button in completes the washer motor circuit to ground and turns the washer motor on, which operates the pump.
The pump allows direct control of the amount of solution delivered to the back glass and shuts off as soon as the wash button is released. The wiper will continue to operate until the dash switch is returned to the "OFF" position.
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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.