Second Design
WARNING: This page is about a different car, the 1999 Cadillac Catera. However, it is still accessible from the selected car via links, so may be relevant.
With this system, Remote Control Door Lock Receiver (RCDLR) is integrated into Body Control Module (BCM). Transmitter sends signals directly to BCM. The BCM then locks/unlocks doors, opens trunk or opens fuel filler door directly.