2005 Chevrolet Avalanche Owner's Manual - Page 172
2005 Chevrolet Avalanche Manual
Page 172 highlights
Your vehicle has a light sensor located on the top of the instrument panel. Be sure it is not covered, or the system will be on whenever the ignition is on. The system may also turn on your headlamps when driving through a parking garage, heavy overcast weather or a tunnel. This is normal. There is a delay in the transition between the daytime and nighttime operation of the Daytime Running Lamps (DRL) and the automatic headlamp systems so that driving under bridges or bright overhead street lights does not affect the system. The DRL and automatic headlamp system will only be affected when the light sensor sees a change in lighting lasting longer than the delay. If you start your vehicle in a dark garage, the automatic headlamp system will come on immediately. Once you leave the garage, it will take approximately one minute for the automatic headlamp system to change to DRL if it is light outside. During that delay, your instrument panel cluster may not be as bright as usual. Make sure your instrument panel brightness control is in the full bright position. See Instrument Panel Brightness on page 3-17. The fog lamp button is located on the left side of your instrument panel. Press the button to turn the fog lamps on while the headlamps or parking lamps are on. Press the button again to turn them off. An indicator light will glow near 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 the 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. 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. Fog Lamps If your vehicle has fog lamps you can use them for better vision in foggy or misty conditions. Your parking lamps and/or low-beam headlamps must be on for your fog lamps to work. 3-16