Circuit/System Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
When the instrument panel lamps dimmer switch is activated, a variable voltage signal is applied through the LED dimmer switch signal circuit to the body control module (BCM). The BCM then applies a message on the low speed serial data communication circuit to the door switches to illuminate the switch backlighting. The BCM, driver door switch, and passenger door switch then applies a variable voltage signal through the LED dimming supply circuit to the components on that circuit.