2004 GMC Yukon Owner's Manual - Page 174

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 brightness control is in the full bright position. See "Instrument Panel Brightness Control" under Interior Lamps on page 3-18. 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. Your headlamps will also stay on after you exit the vehicle. You can program this feature using the Driver Information Center. See Driver Information Center (DIC) on page 3-56. As with any vehicle, you should turn on the regular headlamp system when you need them. 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 come on when the following conditions are met: The ignition is on The exterior lamps control is AUTO The automatic transmission is not in PARK (P) The light sensor determines it is daytime When the DRL are on, only your DRL lamps 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 automatic headlamp system will switch from DRL to the headlamps or the last chosen headlamp setting that was used. When you turn the headlamp switch off, the headlamps will go off, and your DRL lamps will illuminate, provided it is not dark outside. Lamps On Reminder A reminder chime will sound when your headlamps or parking lamps are manually turned on and your ignition is off, in LOCK, ACCESSORY, or your door is open. To disable the chime, turn the light off then back on. 3-16