Circuit/System Description

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The outside rearview mirror courtesy lamps are located on the driver and passenger outside rearview mirrors and are used to illuminate the vehicles entry point. When a door is opened or a lock/unlock request from the key fob is performed, the body control module (BCM) communicates via serial data with the driver and passenger door lock/window switches requesting the outside rearview mirror courtesy lamps be illuminated. The driver and passenger door lock/window switches provide each LED with a voltage signal circuit and when the request to command the LED's ON is received from the BCM, the driver and passenger door lock/window switches respond to the request by switching the control circuit to ground allowing voltage to flow from the signal circuits illuminating each LED located in the lower portion of the driver and passenger outside rearview mirrors.