Rear Window Washer

The wiper/washer switch is provided voltage when the ignition is ON. The voltage passes through 2 internal switches and is routed through the BCM to the washer pump. When the washer is not activated, voltage is present on both cirucits to the washer pump. When the rear washer switch is activated, ground is provided on one of the circuits instead of voltage, activating the washer pump.

The BCM monitors for ground on both circuits as they pass through it. When the rear window washer switch is activated, one of the circuits is routed to ground indicating a rear window washer request. When BCM detects the request, it activates the rear window wiper and the washer pump for as long as the washer request is detected. The rear wiper wipes 2-3 more times after the washer pump turns off. After a brief pause, an additional courtesy wipe follows.