GMC 2006 Sierra - Manual (Page 193)

Daytime Running Lamps (DRL)
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 in 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.
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.
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. 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.
Turning off the automatic headlamp system with the
headlamp switch is not available for vehicles first sold in
Canada. For vehicles first sold in Canada, you can turn
off the automatic headlamp system when parked at
night by applying the parking brake before starting your
vehicle. The headlamps will remain off once the vehicle is
started for as long as you are parked. If you release the
parking brake, the lights will turn on. If the parking brake
is not released before you begin to drive, the exterior
lamps will turn on above 2 mph (3.2 km/h).
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