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1999 GMC Yukon Denali Owners Manual - Exterior Lamps



Exterior Lamps

Your parking/headlamp knob is on the left side of your instrument panel.

Turn the knob clockwise, to the parking lamp symbol, to turn on the following:

  • Parking Lamps
  • Sidemarker Lamps
  • Taillamps
  • License Plate Lamps
  • Instrument Panel Lights

Turn the knob clockwise again, to the master lighting symbol, to turn on all the lamps listed as well as the headlamps.

Turn the knob counterclockwise, to OFF, to turn off your lamps. For additional information on headlamp operation, see “Headlamp Delay” in the Index.

You can switch your headlamps from high to low beam by pulling on the turn signal/high-beam lever.

A circuit breaker protects your headlamps. If you have an electrical overload, your headlamps will flicker on and off. Have your headlamp wiring checked right away if this happens.

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.

To idle your vehicle with the automatic headlamp system off, set the parking brake while the ignition is off. Then start the vehicle. The automatic headlamp system will stay off until you release the parking brake. Use the headlamp switch to turn on the regular lamps when needed

Headlamps-On Reminder

A chime will sound when your headlamps are turned on and your ignition is in OFF, LOCK or ACCESSORY.

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.

The DRL system will make your headlamps come on at a reduced brightness when:

  • the ignition is on,
  • the headlamp switch is off,
  •  the parking brake is released and
  •  it is bright enough outside and the automatic headlamps are off.

When the DRL are on, only your headlamps will be on. The taillamps, sidemarker and other lamps won’t be on. Your instrument panel won’t be lit up either.

When it begins to get dark, your DRL will turn off. Your headlamps will come on automatically.

When it begins to get bright, the regular lamps will go off, and your headlamps will change to the reduced brightness of DRL.

To idle your vehicle with the DRL off, set the parking brake. The DRL will stay off until you release the parking brake

As with any vehicle, you should turn on the regular headlamp system when you need it.

Fog Lamps

Your vehicle has fog lamps. Use them for better vision in foggy or misty conditions. Your parking lamps and/or low-beam headlamps must be on for your fog lamps to work. Fog lamps are not meant to be used without headlamps in the dark.

The fog lamp switch is located to the right of the instrument panel cluster.

Press the ribbed top part of the switch to turn the fog lamps on. Press the bottom of the switch to turn them off. An indicator light will illuminate in the switch when the fog lamps are on.

Fog lamps will go off whenever your high-beam headlamps come on. When the high-beams are off, the fog lamps will come on again.

Headlamp Delay

Your vehicle is equipped with a headlamp delay feature that holds the headlamps on for a short period of time after the ignition is turned off.

The HEADLAMP DELAY button is located on the lower left side of the inside rearview mirror

The length of time that the headlamps stay on after the ignition is turned off can be adjusted by pressing and holding the HEADLAMP DELAY button. The delay can be varied in five steps (0, 15, 30, 60 and 90 seconds). When the HEADLAMP DELAY button is held in, the Light Emitting Diode (LED) on the mirror will show five step changes in brightness. When the LED is at its brightest the headlamp delay will be 90 seconds, and when it is most dim the delay will be zero seconds.


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