2004 Chevrolet Colorado Owner's Manual - Page 143

Automatic Headlamp System Your vehicle may be equipped with this feature. When it is dark enough outside, your automatic headlamp system will turn on your headlamps at the normal brightness along with other lamps such as the taillamps, sidemarker, parking lamps and the instrument panel lights. The radio lights may also be dim. Your vehicle may have 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 system 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 several seconds 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" under Interior Lamps on page 3-17. Lamps On Reminder If a door is open, a reminder chime will sound when your headlamps or parking lamps are manually turned on and your key is out of the ignition. To turn off the chime, turn the headlamp switch to off and then back on. In the automatic mode, the headlamps turn off once the ignition is in LOCK. 3-15