2004 Chevrolet Tahoe Owner's Manual - Page 172

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. 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. Shifting the transmission into PARK (P) will allow you to idle the vehicle with the DRL off. The DRL will stay off until you shift the transmission out of PARK (P). This procedure applies only to vehicles first sold in the United States. 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 3-16