Circuit/System Description
WARNING: This page is about a different car, the 2016 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
When the body control module (BCM) receives a command to activate the door dead locks, the BCM will apply voltage to the door lock security printed circuit board relay. This will energize the relay closing the contacts and enable the BCM to supply voltage to the dead locks in each of the doors.