Low Speed Operation
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.
With the wiper switch in the low position, the body control module (BCM) detects a signal in the windshield wiper switch low signal circuit. The BCM then applies voltage to the WIPER relay control circuit. This energizes the WIPER relay and allows voltage to be applied through the switched contacts of the of the WIPER relay to the normally open switched contacts of the WIPER HI relay. Voltage is then applied from the WIPER HI relay normally open contacts to the low control circuit of the windshield wiper motor.