Circuit Description
WARNING: This page is about a different car, the 1999 GMC Sierra and 1999 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The remote control door lock receiver is supplied voltage at all times from TBC fuse CKT 1140 (ORN). Ground is supplied on CKT 1850 (BLK) to G203.
When a button transmitter (key fob), is depressed, receiver sends a wake-up signal to Body Control Module (BCM) on CKT 416. Along with wake up message, receiver sends command to unlock, lock, or panic mode to BCM. If there is no DTC associated with requested command, BCM will lock, unlock doors or place vehicle in panic mode, flash exterior lights and sound horn.
The BCM supplies a small voltage on CKT 416 called a bias voltage which enables messages to travel from remote control door lock receiver to BCM. The BCM also sends messages to remote control door lock receiver (program mode).