brake sensor GMC YUKON XL 2002 Owners Manual

2-38Automatic 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 dim.
Your vehicle is equipped with a headlamp off delay,
which will keep the headlamps on for a short time after
the ignition is turned to OFF. For more information see
ªSecondary Information Center (SIC)º in the Index.
Your vehicle has a light sensor located on the top of the
instrument panel in the defroster grille. Be sure it is not
covered, or the system will be on whenever the ignition
is on.
The system may also turn on your headlamps when
driving through a parking garage, heavy overcast
weather or a tunnel. This is normal.
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 sees
a change in lighting lasting longer than the delay. To idle your vehicle with the automatic headlamp
system off, set the parking brake while the ignition is
off. Then start your vehicle. The automatic headlamp
system will stay off until you release the parking brake.
As with any vehicle, you should turn on the regular
headlamps when you need them.
You may be able to turn off your automatic headlamp
system. See ªDaytime Running Lamps (DRL)º later in
this section for more information.
Lamps On Reminder A reminder chime will sound when your headlamps or
parking lamps are manually turned on and your ignition
is in OFF, LOCK or ACCESSORY. To disable the
chime, turn the thumbwheel all the way down. In the
automatic mode, the headlamps turn off once the
ignition key is in OFF.

2-39Puddle Lamps Your vehicle is equipped with puddle lamps to help you
see the area near the base of the front doors when it is
dark out. The puddle lamps will illuminate when a door
is opened or when you press the UNLOCK button on the
keyless entry transmitter. The lamps will time out or
turn off once the engine is started.
You can program the puddle lamps not to come on if
you choose. See ªSecondary Information Centerº in the
Index for more information.
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 ignition is on,

the exterior lamps control is off,

the automatic transmission is not in PARK (P),

the light sensor determines it is daytime and

the parking brake is released.
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 exterior lamps control to the off
position, the headlamps will go off, and your DRL
lamps will illuminate, provided it is not dark outside.
To idle your vehicle with the DRL off, set the parking
brake. Shifting the transmission into PARK (P) will also
allow you to idle the vehicle with the DRL off. The
DRL will stay off until you release the parking brake
or shift the transmission out of PARK (P).