Circuit/System Description
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
The body control module monitors the cargo door ajar signal circuit. When the cargo door is open or ajar the ajar switch closes providing a ground path for the ajar signal circuit. The body control module will detect the voltage drop in the signal circuit and will send a serial data message to the driver information center to display the Cargo Door Open message