headlamp GMC YUKON 1999 User Guide

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2-47 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.
The headlamp switch can always be used to turn on the
regular lamps. As with any vehicle, you should turn on
the regular headlamp system when you need it.
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.

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2-48 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.
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.
Remember, fog lamps alone will not give off as much
light as your headlamps. Never use your fog lamps in
the dark without turning on your headlamps.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.

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2-49
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.
Interior Lamps
Instrument Panel Intensity Control
The instrument panel intensity control is located next to
the parking/headlamp switch. Turn the thumbwheel up
to adjust the instrument panel lights. Turn the
thumbwheel up to the first notch to return the radio
display and gear shift indicator LED display to full
intensity when the headlamps or parking lamps are on.
To turn on the dome lamps (with the vehicle doors
closed) turn the thumbwheel up to the second
notch position.
Exit Lighting and Delayed Illumination
With this feature, your interior lamps will come on and
stay on for up to 25 seconds when entering the vehicle
and up to 5 seconds when leaving your vehicle.
When the doors are opened, the dome lamps will only
come on if the dome lamp button is in the out position.
When all doors are closed or the dome lamp button is
pressed in, the lamps will stay on for a short period of
time and will then fade out.
Dome Lamps
The dome lamps will come on when you open the doors.
You can also turn the dome lamps on by turning the
thumbwheel, located next to the parking/headlamps
switch knob, all the way up to the second notch. In this
position, the dome lamps will remain on whether the
doors are opened or closed.

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You can use the DOME OVERRIDE button, located
below the parking/headlamp knob, to set the dome
lamps to come on automatically when the doors are
opened, or remain off. To turn the lamps off, press the
button once. With the button in this position, the dome
lamps will remain off when the doors are open. To
return the lamps to automatic operation, press the button
again and return it to the ªoutº position. With the button
in this position, the dome lamps will come on when you
open the door.
Reading Lamps
Your vehicle has reading
lamps. Press the button next
to the lamp to turn the
lamp on.
The lamps can be adjusted to point in the direction
you want.
Press the button again to turn the lamp off.
Battery Rundown Protection
This feature shuts off the dome, courtesy, vanity,
reading, glove box and underhood lamps if they are left
on for more than 20 minutes when the ignition is off.
This will keep your battery from running down.

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2-51
Mirrors
Electrochromic Inside Rearview Mirror
with Compass, Temperature Display and
Headlamp Delay
Your vehicle has electrochromic inside and outside
rearview mirrors. Your vehicle also has a headlamp
delay feature. See ªHeadlamp Delayº in the Index for
more information.
When on, an electrochromic mirror automatically dims
to the proper level to minimize glare from lights behind
you after dark.
The mirror also includes an eight-point compass display
in the upper right corner of the mirror face. When on,
the compass automatically calibrates as the vehicle
is driven.
The mirror also includes a display in the upper right
corner of the mirror. This can be used as a compass or to
indicate outside air temperature.

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To turn on the auto-dimming feature, press and hold the
inside rearview mirror TEMP button for eight seconds.
See ªElectrochromic Inside Rearview Mirror with
Compass, Temperature Display and Headlamp Delayº in
the Index for further information.
To turn on the defrost feature, press the rear window
defrost button. See ªRear Window Defoggerº in the
Index for further information.
Convex Outside Mirror
Your passenger's side mirror is convex. A convex
mirror's surface is curved so you can see more from the
driver's seat.
CAUTION:
A convex mirror can make things (like other
vehicles) look farther away than they really are.
If you cut too sharply into the right lane, you
could hit a vehicle on your right. Check your
inside mirror or glance over your shoulder before
changing lanes.
Storage Compartments
Your vehicle has a variety of storage compartments
designed to store small items.
Glove Box
To open your glove box, move the release button toward
the passenger's side and pull the door open.
Center Overhead Console
Your vehicle has an overhead console. It has storage
compartments inside it. Your vehicle also has a
Universal Transmitter. See ªUniversal Transmitterº in
the Index.
Sunglasses Compartment
The center overhead compartment can be used to
conveniently store your sunglasses.
To open the center compartment, press the release
button located at the rear of the compartment door.
Place your sunglasses in the compartment door with the
lenses facing out.

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2-81 Daytime Running Lamps (DRL)
Indicator Light
This light will go on
whenever the DRL are on.
When it begins to get dark, the DRL indicator light will
turn off and your automatic headlamps will turn on.
Check Gages Light
This light will come on
briefly when you are
starting the engine.
If the light comes on and stays on while you are driving,
it could indicate a problem with your vehicle. It could bea problem with your oil pressure, coolant temperature,
or some other problem. Check your various gages to see
if they are in the warning zones. If they are, have your
vehicle serviced right away.
Headlamp High-Beam Indicator Light
The high-beam indicator is
on whenever you use your
high
-beam headlamps. For
more details about high
beams, see ªHeadlamp
High/Low
-Beam Changerº
in the Index.
Turn Signal and Lane Change
Indicator Lights
The signal indicator will
come on whenever you
signal a turn or lane change.
See ªTurn Signal and Lane
Change Indicatorº in
the Index.

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4-20

Ease up on your speed as you approach the top of
the hill.

Attach a flag to the vehicle to make you more visible
to approaching traffic on trails or hills.

Sound the horn as you approach the top of the hill to
let opposing traffic know you're there.

Use your headlamps even during the day. They make
you more visible to oncoming traffic.
CAUTION:
Driving to the top (crest) of a hill at full speed can
cause an accident. There could be a drop
-off,
embankment, cliff, or even another vehicle. You
could be seriously injured or killed. As you near
the top of a hill, slow down and stay alert.
Q:What should I do if my vehicle stalls, or is about
to stall, and I can't make it up the hill?
A:If this happens, there are some things you should
do, and there are some things you must not do.
First, here's what you should do:

Push the brake pedal to stop the vehicle and
keep it from rolling backwards. Also, apply the
parking brake.

If your engine is still running, shift the transmission
to REVERSE (R), release the parking brake, and
slowly back down the hill in REVERSE (R).

If your engine has stopped running, you'll need to
restart it. With the brake pedal pressed and the parking
brake still applied, shift the transmission to PARK (P)
and restart the engine. Then, shift to REVERSE (R),
release the parking brake, and slowly back down the
hill as straight as possible in REVERSE (R).

As you are backing down the hill, put your left hand
on the steering wheel at the 12 o'clock position. This
way, you'll be able to tell if your wheels are straight
and maneuver as you back down. It's best that you
back down the hill with your wheels straight rather
than in the left or right direction. Turning the wheel
too far to the left or right will increase the possibility
of a rollover.

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Driving at Night
Night driving is more dangerous than day driving. One
reason is that some drivers are likely to be impaired
-- by
alcohol or drugs, with night vision problems, or by fatigue.Here are some tips on night driving.

Drive defensively.

Don't drink and drive.

Since you can't see as well, you may need to
slow down and keep more space between you and
other vehicles.

Slow down, especially on higher speed roads. Your
headlamps can light up only so much road ahead.

In remote areas, watch for animals.

If you're tired, pull off the road in a safe place
and rest.

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4-29 Night Vision
No one can see as well at night as in the daytime. But as
we get older these differences increase. A 50
-year-old
driver may require at least twice as much light to see the
same thing at night as a 20
-year-old.
What you do in the daytime can also affect your night
vision. For example, if you spend the day in bright
sunshine you are wise to wear sunglasses. Your eyes will
have less trouble adjusting to night. But if you're
driving, don't wear sunglasses at night. They may cut
down on glare from headlamps, but they also make a lot
of things invisible.
You can be temporarily blinded by approaching
headlamps. It can take a second or two, or even several
seconds, for your eyes to readjust to the dark. When you
are faced with severe glare (as from a driver who
doesn't lower the high beams, or a vehicle with
misaimed headlamps), slow down a little. Avoid staring
directly into the approaching headlamps.Keep your windshield and all the glass on your vehicle
clean
-- inside and out. Glare at night is made much
worse by dirt on the glass. Even the inside of the glass
can build up a film caused by dust. Dirty glass makes
lights dazzle and flash more than clean glass would,
making the pupils of your eyes contract repeatedly.
Remember that your headlamps light up far less of a
roadway when you are in a turn or curve. Keep your
eyes moving; that way, it's easier to pick out dimly
lighted objects. Just as your headlamps should be
checked regularly for proper aim, so should your eyes
be examined regularly. Some drivers suffer from night
blindness
-- the inability to see in dim light -- and
aren't even aware of it.