headlamp GMC ENVOY 1999 User Guide

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Mirrors
Electrochromic Day/Night Inside
Rearview Mirror
This mirror automatically changes to reduce glare from
headlamps behind you. A photocell on the back of the
mirror senses when it is becoming dark outside. Another
photocell built into the mirror surface senses when
headlamps are behind you.
At night, when the glare is too high, the mirror will
gradually darken to reduce glare (this change may take a
few seconds). The mirror will return to its clear daytime
state when the glare is reduced. The mirror will also
return to its clear daytime state when the vehicle is put
into REVERSE (R).
Press the AUTO button at the base of the mirror to turn
on the automatic feature. The button has an indicator
light to show it is on. Press the OFF button to turn the
automatic feature off.
Time Delay
The automatic mirror has a time delay feature which
prevents unnecessary switching from the night back to
the day position. This delay prevents rapid changing of
the mirror as you drive under lights and through traffic.
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Cleaning the Photocells
Use a cotton swab and glass cleaner to clean the
photocells when necessary.
Power Remote Control Mirror
The control is located on the
driver's door armrest.
Move the upper control to the left or right to choose the
mirror, then press the arrows on the control pad to adjust
the mirror.
Convex Outside Mirror
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 or left lane,
you could hit a vehicle. Check your inside mirror
or glance over your shoulder before
changing lanes.
Heated Outside Rearview Mirror
When you operate the rear window defogger, a defogger
also warms the heated driver's and passenger's outside
rearview mirrors to help clear them of ice, snow and
condensation. See ªRear Window Defoggerº in the
Index for more information.
Electrochromic Rearview Outside Mirror
Only the driver's side outside mirror will adjust for the
glare of headlamps behind you. See ªElectrochromic
Day/Night Inside Rearview Mirrorº earlier in
this section.
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4-20 Driving Uphill
Once you decide you can safely drive up the hill, you
need to take some special steps.

Use a low gear and get a firm grip on the
steering wheel.

Get a smooth start up the hill and try to maintain
your speed. Don't use more power than you need,
because you don't want your wheels to start spinning
or sliding.

Try to drive straight up the hill if at all possible. If
the path twists and turns, you might want to find
another route.
CAUTION:
Turning or driving across steep hills can be
dangerous. You could lose traction, slide
sideways, and possibly roll over. You could be
seriously injured or killed. When driving up hills,
always try to go straight up.

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.
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Your vehicle will require more frequent service due to
off
-road use. Refer to the Maintenance Schedule for
additional information.
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.
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.
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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.
Driving in Rain and on Wet Roads
Rain and wet roads can mean driving trouble. On a wet
road, you can't stop, accelerate or turn as well because
your tire
-to-road traction isn't as good as on dry roads.
And, if your tires don't have much tread left, you'll get
even less traction. It's always wise to go slower and be
cautious if rain starts to fall while you are driving. The
surface may get wet suddenly when your reflexes are
tuned for driving on dry pavement.
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4-30 Hydroplaning
Hydroplaning is dangerous. So much water can build up
under your tires that they can actually ride on the water.
This can happen if the road is wet enough and you're
going fast enough. When your vehicle is hydroplaning,
it has little or no contact with the road.
Hydroplaning doesn't happen often. But it can if your
tires do not have much tread or if the pressure in one or
more is low. It can happen if a lot of water is standing on
the road. If you can see reflections from trees, telephone
poles or other vehicles, and raindrops ªdimpleº the
water's surface, there could be hydroplaning.
Hydroplaning usually happens at higher speeds. There
just isn't a hard and fast rule about hydroplaning. The
best advice is to slow down when it is raining.
Driving Through Deep Standing Water
NOTICE:
If you drive too quickly through deep puddles or
standing water, water can come in through your
engine's air intake and badly damage your
engine. Never drive through water that is slightly
lower than the underbody of your vehicle. If you
can't avoid deep puddles or standing water, drive
through them very slowly.
Some Other Rainy Weather Tips

Turn on your low-beam headlamps -- not just your
parking lamps
-- to help make you more visible
to others.

Besides slowing down, allow some extra following
distance. And be especially careful when you pass
another vehicle. Allow yourself more clear room
ahead, and be prepared to have your view restricted
by road spray.

Have good tires with proper tread depth.
(See ªTiresº in the Index.)
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CAUTION:
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill
you. You can't see it or smell it, so you might not
know it is in your vehicle. Clear away snow from
around the base of your vehicle, especially any
that is blocking your exhaust pipe. And check
around again from time to time to be sure snow
doesn't collect there.
Open a window just a little on the side of the
vehicle that's away from the wind. This will help
keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little faster
than just idle. That is, push the accelerator slightly. This
uses less fuel for the heat that you get and it keeps the
battery charged. You will need a well
-charged battery to
restart the vehicle, and possibly for signaling later on
with your headlamps. Let the heater run for a while.Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine again
and repeat this only when you feel really uncomfortable
from the cold. But do it as little as possible. Preserve the
fuel as long as you can. To help keep warm, you can get
out of the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.
Recreational Vehicle Towing
There may be times when you want to tow your vehicle
behind another vehicle for use at your destination. Be
sure to use the proper towing equipment designed for
recreational vehicle towing. Follow the instructions for
the towing equipment.
When towing your vehicle, turn the ignition to OFF. To
prevent your battery from draining while towing,
remove the RDO BATT fuse from the instrument panel
fuse block. Be sure to replace the fuse when you reach
your destination. See ªFuses and Circuit Breakersº in
the Index.
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6-32 High Intensity Discharge (HID) Lighting
CAUTION:
The low beam High Intensity Discharge lighting
system operates at a very high voltage. If you try
to service any of the system components, you
could be seriously injured. Have your dealer or a
qualified technician service them.
Halogen Bulbs
CAUTION:
Halogen bulbs have pressurized gas inside and
can burst if you drop or scratch the bulb. You or
others could be injured. Be sure to read and
follow the instructions on the bulb package.
Headlamps
Composite High-Beam Headlamp System
1. Open the hood.
2. Remove the black retainer clips by lifting up.
3. Pull the headlamp assembly out.
4. Unplug the electrical connector.
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5. Turn the bulb assembly counterclockwise to
remove it.
6. Put the new bulb assembly into the headlamp
assembly and turn it clockwise until it is tight.
7. Plug in the electrical connector.
8. Put the headlamp assembly back into the vehicle.
Install the two retaining clips.
Front Turn Signal Lamp Assembly
1. Remove the headlamp assembly as shown under
ªComposite High
-Beam Headlamp Systemº earlier
in this section.
2. Twist the bulb socket to remove it from the
headlamp assembly.
3. Pull the bulb straight out to remove it from
the socket.
4. Push the new bulb into the socket until it snaps
into place.
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5. Put the bulb socket into the lamp assembly and twist
it clockwise until it is tight.
6. Put the headlamp assembly back into the vehicle.
Install the two retaining clips.
Taillamps
1. Open the liftgate.
2. Remove the two screws
from the lamp assembly.3. Pull the assembly away from the vehicle.
4. Turn the socket counterclockwise to remove it. Push
the tab in while you turn the socket counterclockwise.
5. Holding the base of the bulb, pull the bulb straight
out of the socket.
6. Push the new bulb straight into the socket until
it clicks.
7. Put the socket into the assembly and turn the socket
clockwise until it locks in place.
8. Install the lamp assembly. Install and tighten
the screws.
9. Close the liftgate.
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