GM Service Manual Online
For 1990-2009 cars only

Whenever the ignition switch is in the ON or the START position, battery voltage applies through the WIP fuse to the rear wiper and washer switches and to the rear wiper motor switch.

Washer Operation

When the rear washer switch is pressed, battery voltage applies through the wash switch contacts to the rear washer pump. The rear washer pump permanently grounds at G104 and will operate as long as the washer switch is engaged. In order to initiate wiper operation, battery voltage is also applied to another set of rear washer contacts to the rear wiper motor. This action applies voltage to the rear wiper motor, which is permanently grounded. The motor will continue to operate as long as the washer switch is engaged.

The rear wiper motor pawl and switch will engage as the motor turns, and the contacts will remain closed until the wiper is in the park position. While the pawl and switch contacts are closed, voltage applies to the rear wiper motor through these components:

    • The WIP fuse.
    • The OFF contacts of the rear wiper switch.
    • The rear wiper motor pawl and switch contacts.

This action allows the rear wiper to complete at least one sweep after the wash switch has been released.

Wiper Operation

When the rear wiper switch is pressed, the switch mechanism locks the contacts of the rear wiper switch to the closed position. Battery voltage then applies through the following components:

    • The WIP fuse.
    • The rear wiper switch.
    • The rear wiper motor.

Since the rear wiper motor is permanently grounded, the motor operates as long as the rear wiper switch contacts remain in the closed position. When the rear wiper switch is pressed again, the mechanism releases the contacts to the open position. The contacts release but the pawl and switch assembly provides voltage to the rear wiper motor until the wiper is in the park position.