Circuit/System Description
WARNING: This page is about a different car, the 2016 GMC Acadia, 2016 Chevrolet Traverse, and 2016 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
When the transmission is placed into REVERSE while engine is running, a 12 V signal is sent to the inside rearview mirror and rearview camera indicating that camera operation is requested. Ignition voltage and ground are supplied to the rearview camera; the inside rearview mirror is supplied a common ignition voltage and ground source that is shared with other mirror operations. The rearview camera sends video information to the inside rearview mirror through a video signal + and a video signal - circuit. A grounded shielding also wraps the video signal circuits to reduce electronic interference which may degrade the video signal and cause a distorted or otherwise degraded image.