Circuit/System Description
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) controls the door lock, passenger door unlock and driver door unlock relays. Voltage is applied to the appropriate relay through the door lock/unlock control circuit when the BCM detects a door lock/unlock switch activation or a keyless entry lock or unlock command.