brake sensor GMC YUKON XL DENALI 2001 Owners Manual

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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
headlamp system when you need it.
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.
Puddle 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 headlamp knob is in automatic headlamp mode,

the automatic transmission is not in PARK (P),

the light sensor determines it is daytime and

the parking brake is released.