GM Service Manual Online
For 1990-2009 cars only

Hatch Ajar Indicator Circuit Description for GMC Truck Yukon XL - 4WD 2000

The Body Control Module (BCM) monitors the cargo door or the Liftgate and Liftglass Ajar switch(s). When the switch closes to ground, the BCM sends a class 2 message to the cluster to display the "CARGO DOOR AJAR" message.