Circuit/System Description
WARNING: This page is about a different car, the 2010 Chevrolet HHR. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) illuminates the stop lamps by applying battery positive voltage to the stop lamp supply voltage circuit. The electronic brake control module (EBCM) receives a voltage input from the stop lamp supply voltage circuit to determine if the brake pedal is applied.