2005 GMC Yukon Owner's Manual - Page 167

Fog Lamps If your vehicle has fog lamps, use them for better vision in foggy or misty conditions. The fog lamp button is located on the left side of the instrument panel. The fog lamps will be cancelled after the ignition is turned off. If you still want to use the fog lamps after you restart the vehicle, you will need to press the fog lamp button again. 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. Your parking lamps and/or low-beam headlamps must be on for your fog lamps to work. Press the button to turn the fog lamps on. Press the button again to turn them off. An indicator light will glow in the button when the fog lamps are on. Remember, fog lamps alone will not give off as much light as your headlamps. Never use your fog lamps in the dark without turning on your headlamps. The fog lamps will go off whenever your high-beam headlamps come on. When the high beams go off, the fog lamps will come on again. 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. 3-17