Wash Operation
WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
In the WASH position windshield wiper/washer switch supplies a ground signal to the BCM. The BCM monitors for a Low signal condition on this circuit to detect when a WASH cycle is requested. After a short delay, the BCM energizes the Wiper relay which will operate the windshield wiper motor at low speed. The wiper motor will continue to operate for 2 wipe cycles after the wash switch is released.