Gate Ajar Indicator
WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.
The IPC illuminates the GATE AJAR indicator when the body control module (BCM) detects that the rear hatch is ajar or open (signal circuit is low). The IPC receives a class 2 message from the BCM requesting illumination. If the vehicle is in the forward or reverse gear position, the BCM activates an audible warning.