2007 GMC Sierra 1500 Pickup Owner's Manual - Page 226

Auxiliary Roof Mounted Lamp If your vehicle has this feature, this button includes wiring provisions for a dealer or a qualified service center to install an auxiliary roof lamp. This button is located on the center of the instrument panel near the climate controls. Instrument Panel Brightness D (Instrument Panel Brightness): This feature controls the brightness of the instrument panel lights. The thumbwheel for this feature is located next to the headlamp control. Move the thumbwheel up to adjust the instrument panel lights and to return the radio display to full brightness when the headlamps or parking lamps are on. To turn on the dome lamps, move the thumbwheel to the farthest position. Dome Lamps When the wiring is connected to an auxiliary roof mounted lamp, pressing the button will activate the lamp and illuminate an indicator light near the button. Pressing the button again will turn off the roof mounted lamp. If your vehicle has this button, your vehicle may have the snow plow prep package. For further information see Adding a Snow Plow or Similar Equipment on page 416. 226 The dome lamps come on when a door is opened. The dome lamps can be turned on by moving the thumbwheel, located next to the exterior lamps control, to the farthest position. In this position, the dome lamps will remain on whether a door is opened or closed.