Circuit Description
WARNING: This page is about a different car, the 2005 Buick LaCrosse and 2005 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) receives a signal from the brake pedal position sensor through the stop lamp switch signal circuit. The BCM then applies voltage through the stop lamp voltage supply circuit to the powertrain control module (PCM), electronic brake control module (EBCM), and the stop lamps.