2007 GMC Sierra 1500 Pickup Owner's Manual - Page 223

The DRL system will come on when the following conditions are met: • The ignition is on • The exterior lamps control is in AUTO • The light sensor determines it is daytime When the DRL are on, only your DRL lamps will be on. The taillamps, sidemarker, and other lamps will not be on. The instrument panel back lighting will not be on either. When it begins to get dark, the automatic headlamp system will switch from DRL to the headlamps. When you turn the headlamp switch off, the headlamps will go off. Automatic Headlamp System When it is dark enough outside, the automatic headlamp system will turn on the headlamps at the normal brightness, along with the taillamps, sidemarker, parking lamps, and the instrument panel lights. The radio back lighting will also be dimly lit. To turn off the automatic headlamp system, turn the exterior lamps switch to the off position. Turning off the automatic headlamp system with the headlamp switch is not available for vehicles first sold in Canada. Your vehicle has a light sensor located on the top of the instrument panel in the defroster grille that regulates when the automatic headlamps turn on. Be sure it is not covered, or the headlamps will come on whenever the ignition is on. 223