Circuit/System Description
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) controls and monitors the state of the wiper control circuit. When the windshield wiper switch is placed in to a low speed setting, a signal is applied to the BCM. The BCM then applies battery positive voltage to the coil side of the wiper relay through the wiper relay control circuit. This energizes the wiper relay, allowing battery positive voltage from the wiper/ws fuse through the switched side of the wiper relay to the windshield wiper motor. Ground is applied at all times to the coil side of the wiper relay and the windshield wiper motor form G201.