2002 GMC Sonoma Owner's Manual - Page 118

(Headlamps): Turning the exterior lamps control to this position turns on the headlamps, together with the previously listed lamps and lights. (Off): Turn the exterior lamps control all the way counterclockwise to turn off the lamps and put the system in automatic headlamp mode. 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 dim. Your vehicle is equipped with a light sensor on the top of the instrument panel under the radio speaker grill. 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. As with any vehicle, you should turn on the regular headlamps when you need them. You may be able to turn off your Automatic Headlamp System. See "Daytime Running Lamps (DRL)" later in this section for more information. Lamps On Reminder A reminder chime will sound when your headlamps or parking lamps are manually turned on and your ignition is in OFF, LOCK or ACCESSORY. To turn the chime off, turn the exterior lamps control all the way counterclockwise to OFF or turn the instrument panel dimmer down to the fully dimmed position. In automatic mode, the headlamps turn off once the ignition key is in OFF. 2-48