GM Service Manual Online
For 1990-2009 cars only

The rear wiper module controls rear wiper motor operation. Battery voltage supplied to the module is used to operate the wiper motor in all modes and to return the rear wiper arm to the park position after the ignition is turned off. Accessory voltage supplied to the rear wiper/washer switch is used to supply the rear window wiper and washer switch signal circuits. In wiper switch positions 1, 2 and WASH the wiper switch signal circuit voltage level to the wiper motor module determines the wiper motor operating mode. A second wash switch contact is used as the washer pump relay control circuit and the washer pump relay will remain energized for as long as the rear washer switch is pressed. The liftgate ajar switch signal circuit provides information to the rear window wiper module about the status of the liftgate. If the liftgate or liftglass is open the rear wiper operation is not performed.