Circuit/System Description
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The rear wiper washer control module controls the washer motor based on an input from the windshield washer switch, The BCM monitors the washer switch through the windshield washer switch signal circuit. When the WASH switch is closed, ground is supplied to the windshield washer switch signal circuit. When this is seen, the rear wiper washer control module will command the rear washer fluid pump on.