Hatch Open Indicator
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) monitors the voltage level of the liftgate ajar signal circuit which is normally at the system voltage when the hatch is closed. When the liftgate is ajar or open, a switch within the liftgate latch closes providing a path to ground for the liftgate ajar signal circuit. The voltage within the signal circuit will then drop to 0 V, the BCM will then detect the voltage drop and will send a serial data message to the instrument panel cluster (IPC). The IPC will then display an icon of the vehicle with the liftgate open.