2004 GMC Envoy Owner's Manual - Page 138

Fog Lamps Your vehicle may have this feature. Use your fog lamps for better vision in foggy or misty conditions. Your ignition must be in RUN for your fog lamps to work. The fog lamp button is located on the instrument panel to the right of the exterior lamps knob. Interior Lamps Instrument Panel Brightness Press the knob located next to the exterior lamps knob to extend it. Press the button to turn the fog lamps on. Press the button again to turn them off. A light will glow near the button while the fog lamps are on. Fog lamps will turn off whenever your high-beam headlamps are on. Turn the knob to adjust the instrument panel lights. Turn the knob all the way up to turn on the interior lamps. Press the knob back into its stored position when you're not using it. 3-18