2012 GMC Sierra Owner's Manual - Page 207

Lighting The emergency roof lamp circuit is fused at 30 amps, so the total current draw of the attached lamps should be less than this value. The attachment points for the roof lamp circuits are two blunt cut wires located above the overhead console, a dark green switched power wire and a black ground wire. This button is located on the overhead console. When the wiring is connected to an auxiliary roof‐mounted lamp, pressing the bottom of the button will activate the lamp and illuminate an indicator light at the bottom of this button. Pressing the top of the button will turn off the roof‐mounted lamp and indicator. For more information on roof mount emergency lamp installation, please visit the GM Upfitter website at www.gmupfitter.com or contact your dealer. If the vehicle has this button, the vehicle may have the snow plow prep package. For further information, see Adding a Snow Plow or Similar Equipment on page 9‑106. 6-7 Interior Lighting Instrument Panel Illumination Control D (Instrument Panel Brightness): This feature controls the brightness of the instrument panel lights and is located next to the exterior lamps control. Push the knob to extend out and then it can be turned. Turn the knob clockwise or counterclockwise to brighten or dim the instrument panel lights. Turning the knob to the farthest clockwise position turns on the dome lamps.