1999 GMC ENVOY Owners Manual

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6-31
Battery
Your new vehicle comes with an ACDelco Freedom

battery. When it's time for a new battery, we recommend
an ACDelco Freedom battery. Get one that has the
replacement number shown on the original
battery's label.
Vehicle Storage
If you're not going to drive your vehicle for 25 days or
more, remove the black, negative (
-) cable from the
battery. This will help keep your battery from
running down.
CAUTION:
Batteries have acid that can burn you and gas
that can explode. You can be badly hurt if you
aren't careful. See ªJump Startingº in the Index
for tips on working around a battery without
getting hurt.
Contact your dealer to learn how to prepare your vehicle
for longer storage periods.
Also, for your audio system, see ªTheft
-Deterrent
Featureº in the Index.
Bulb Replacement
Before you replace any bulbs, be sure that all the lamps
are off and the engine isn't running. See ªReplacement
Bulbsº in the Index.
For any bulb changing procedure not listed in this
section, contact your GMC dealer's service department.
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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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6-33
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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6-34
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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6-35
Windshield Wiper Blade Replacement
Windshield wiper blades should be inspected at least
twice a year for wear or cracking. See ªWiper Blade
Checkº in Section 7 of this manual under Part B ªOwner
Checks and Servicesº for more information.
See ªNormal Maintenance Replacement Partsº in the
Index for the proper type of replacement blade.
NOTICE:
Use care when removing or installing a blade
assembly. Accidental bumping can cause the arm
to fall back and strike the windshield.
1. To remove the old wiper blades, lift the wiper arm
until it locks into a vertical position.A. Blade Assembly
B. Arm Assembly
C. Locking Tab
D. Blade Pivot
E. Hook Slot
F. Arm Hook
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2. Press down on the blade assembly pivot locking tab.
Pull down on the blade assembly to release it from
the wiper arm hook.
3. Remove the insert from the blade assembly. The
insert has two notches at one end that are locked by
the bottom claws of the blade assembly. At the
notched end, pull the insert from the blade assembly.
4. To install the new wiper insert, slide the insert (D),
notched end last, into the end with two blade claws
(A). Slide the insert all the way through the blade
claws at the opposite end (B). The plastic caps (C)
will be forced off as the insert is fully inserted.5. Be sure that the notches are locked by the bottom
claws. Make sure that all other claws are properly
locked on both sides of the insert slots.
A. Claw in Notch
B. Correct Installation
C. Incorrect Installation
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6. Put the blade assembly pivot in the wiper arm hook.
Pull up until the pivot locking tab locks in the
hook slot.
7. Carefully lower the wiper arm and blade assembly
onto the windshield.
Backglass Wiper Blade Replacement
See ªWindshield Wiper Blade Replacementº in this
section for instructions on how to change the backglass
wiper blade. The backglass wiper blade will not lock in
a vertical position like the windshield wiper blade, so
care should be used when pulling it away from
the vehicle.
Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service, see
your GMC Warranty booklet for details.
CAUTION:
Poorly maintained and improperly used tires
are dangerous.

Overloading your tires can cause
overheating as a result of too much friction.
You could have an air
-out and a serious
accident. See ªLoading Your Vehicleº in
the Index.

Underinflated tires pose the same danger as
overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.

Overinflated tires are more likely to be
cut, punctured or broken by a sudden
impact
-- such as when you hit a pothole.
Keep tires at the recommended pressure.

Worn, old tires can cause accidents. If your
tread is badly worn, or if your tires have
been damaged, replace them.
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6-38 Inflation -- Tire Pressure
The Certification/Tire label, which is on the driver's
door edge, above the door latch, shows the correct
inflation pressures for your tires when they're cold.
ªColdº means your vehicle has been sitting for at least
three hours or driven no more than 1 mile (1.6 km).
NOTICE:
Don't let anyone tell you that underinflation or
overinflation is all right. It's not. If your tires
don't have enough air (underinflation), you can
get the following:

Too much flexing

Too much heat

Tire overloading

Bad wear

Bad handling

Bad fuel economy.
NOTICE: (Continued)
NOTICE: (Continued)
If your tires have too much air (overinflation),
you can get the following:

Unusual wear

Bad handling

Rough ride

Needless damage from road hazards.
When to Check
Check your tires once a month or more. Also, check the
tire pressure of the spare tire.
How to Check
Use a good quality pocket
-type gage to check tire
pressure. You can't tell if your tires are properly inflated
simply by looking at them. Radial tires may look
properly inflated even when they're underinflated.
Be sure to put the valve caps back on the valve stems.
They help prevent leaks by keeping out dirt
and moisture.
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