Driver and Passenger Door Ajar Operation
WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) provides a 12V signal to each door ajar switch and the liftgate ajar switch via the ajar switch signal circuit. The door ajar switches are normally open when the door is fully closed. When a door or liftgate is opened, the ajar switch contacts close providing a path to ground. The driver information center displays door ajar icon when the BCM detects that one of the doors or liftgate are open. The instrument cluster receives a serial data message from the BCM indicating the door ajar status.