Automatic Headlamp System - GMC 2008 Yukon Denali Owner's Manual

When it begins to get dark, the automatic headlamp
system will switch from DRL to the headlamps.
To turn off the DRL lamps, turn the exterior lamps
control to the OFF position and then release. For
vehicles first sold in Canada, the transmission must be
in the PARK (P) position, before the DRL lamps can
be turned off.

Automatic Headlamp System

When it is dark enough outside, the automatic headlamp
system will turn on the headlamps at the normal
brightness, along with the taillamps, sidemarker, parking
lamps, and the instrument panel lights. The radio
lights will also be dim.
To turn off the automatic headlamp system, turn the
exterior lamps switch to the off position and then release
it. For vehicles first sold in Canada, the transmission
must be in the PARK (P) position, before the automatic
headlamp system can be turned off.
The vehicle has a light sensor located on the top of the
instrument panel in the defroster grille that regulates
when the automatic headlamps turn on. Be sure it is not
covered, or the headlamps will come on whenever
the ignition is on.
The system may also turn on the headlamps when
driving through a parking garage, heavy overcast
weather, or a tunnel. This is normal.
3-18
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 detects a change in lighting lasting
longer than the delay.
If the vehicle is started in a dark garage, the automatic
headlamp system will come on immediately. Once
the vehicle leaves the garage, it takes approximately
one minute for the automatic headlamp system to
change to DRL if it is bright enough outside. During that
delay, the instrument panel cluster may not be as
bright as usual. Make sure the instrument panel
brightness control is in the full bright position. See
Instrument Panel Brightness on page 3-19.
To idle the vehicle with the automatic headlamp system
off, turn the control to the off position.
The headlamps will also stay on after you exit the
vehicle. This feature can be programmed using the
Driver Information Center (DIC). See DIC Vehicle
Customization (With DIC Buttons) on page 3-64.
The regular headlamp system can be turned on when
needed.