Circuit Description
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.
The body control module (BCM) supplies battery positive voltage to the center high mounted stop lamp (CHMSL), powertrain control module (PCM), engine temperature control (ETC), and anti-lock brake system (ABS) module through the stop lamp supply voltage circuits when the brakes are applied.