Circuit/System Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The BCM supplies a 12V signal to 2 ajar switches to indicate the status of the liftgate. The liftgate ajar switches are normally open when the liftgate and liftglass are fully closed. When the liftgate or liftglass is opened, the ajar switch contacts close providing a path to ground. The instrument panel cluster (IPC) receives a serial data message from the BCM indicating the liftgate ajar status and the driver information center (DIC) will display the REAR ACCESS OPEN message.
The rear window wiper motor also monitors the liftgate ajar signal circuit and will disable the rear wiper function if it detects that the liftgate or liftglass is open or ajar.