2002 GMC Envoy Owner's Manual - Page 116

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. To idle your vehicle with the automatic headlamp system off, set the parking brake while the ignition is off. Then start your vehicle. The automatic headlamp system will stay off until you release the parking brake, or until you shift out of park. 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 it. 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. The DRL system will make your headlamps come on at reduced brightness when the following conditions are met: D The ignition is on, D the exterior lamps knob is in automatic headlamp mode, D the light sensor detects daytime light, and D the transmission is not in PARK (P). When the DRL are on, only your headlamps will be on. The taillamps, sidemarker and other lamps won't be on. The instrument panel won't be lit up either. When it begins to get dark, the headlamps will automatically switch from DRL to the regular headlamps. Lamps On Reminder A reminder tone will sound when your headlamps or parking lamps are manually turned on, the driver's door is open and your ignition is in LOCK or ACCESSORY. To turn the tone off, turn the knob all the way counterclockwise. In the automatic mode, the headlamps turn off once the ignition key is in LOCK. 2-47