2009 GMC Yukon Owner's Manual - Page 202

Fog Lamps For vehicles with fog lamps, the control is located next to the exterior lamps control on the instrument panel, to the left of the steering column. The ignition must be in the ON/RUN position for the fog lamps to come on. This button is located on the overhead console. # (Fog Lamps): Press to turn the fog lamps on or off. A light will come on in the instrument panel cluster. When the fog lamps are turned on, the parking lamps automatically turn on. When the headlamps are changed to high-beam, the fog lamps also go off. When the high-beam headlamps are turned off, the fog lamps will come on again. Some localities have laws that require the headlamps to be on along with the fog lamps. 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. 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. For further information on roof mount emergency lamp installation, please visit the GM Upfitter website at www.gmupfitters.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 4-40. Auxiliary Roof-Mounted Lamp If the vehicle has this feature, this button includes wiring provisions for a dealer or a qualified service center to install an auxiliary roof lamp. 3-18