2003 GMC Sierra 1500 Pickup Owner's Manual - Page 169

Automatic Headlamp System 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 will also be dim. Your vehicle is equipped with a light sensor located on the top of the instrument panel in the defroster grille. 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. brightness control is in the full bright position. See "Instrument Panel Brightness Control'' under Interior Lamps on page3- 17. To idle your vehicle with the automatic headlamp system off, turn the control to the off position. You may be able to turn off your automatic headlamp system. See Daytime Running Lamps (DRL) later in this section for more information. You may be able to turn off your Automatic Headlamp System. See "Daytime Running Lamps (DRL)" later in this section for more information. As with any vehicle, you should turn on the regular headlamp system when you need them. Lamps On Reminder A reminder chime will sound when your headlamps or parking lamps are manually turned on and yourignition is off, in LOCK, ACCESSORY, or your door open. To is disable the chime, turn the light off then backon. Daytime Running Lamps Daytime Running Lamps (DRL) can make it easier for others to see the front of your vehicle during the day. DRL can be helpful in many different driving conditions, but they can be especially helpful in the short periods after dawn and before sunset. Fully functional daytime running lamps are required on all vehicles first sold in Canada. 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 bright enough outside. During that delay, your instrument panel cluster may not be as bright as usual. Make sure your instrument panel 3-14