Front Door Lock Cylinder Switches
WARNING: This page is about a different car, the 2002 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
The door lock cylinder switches located in the driver and passenger doors are a discrete input to the BCM. The BCM utilizes each of these inputs to disarm the CTD system. Inserting a key and turning to the unlock position will disarm the CTD system.