Circuit Description
WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) internally grounds the liftgate lock relay control circuit for the liftgate lock relay when it receives a class 2 message from the driver door module (DDM), passenger door module (PDM), or when a liftgate lock function is activated. When the BCM grounds the liftgate lock relay control circuit the liftgate lock relay is energized and locks the liftgate.