1999 GMC ENVOY hood open

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2-17
NOTICE:
Your engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way
the engine operates. Before adding electrical
equipment, check with your dealer. If you don't,
your engine might not perform properly.
If you ever have to have your vehicle towed, see
the part of this manual that tells how to do it
without damaging your vehicle. See ªTowing
Your Vehicleº in the Index.
Engine Coolant Heater (If Equipped)
In very cold weather, 0
F (-18
C) or colder, the engine
coolant heater can help. You'll get easier starting and
better fuel economy during engine warm
-up. Usually,
the coolant heater should be plugged in a minimum of
four hours prior to starting your vehicle.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located on the driver's side of the engine
compartment, behind the underhood fuse block.
3. Plug it into a normal, grounded 110
-volt AC outlet.
CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the wrong
kind of extension cord could overheat and cause
a fire. You could be seriously injured. Plug the
cord into a properly grounded three
-prong
11 0
-volt AC outlet. If the cord won't reach, use a
heavy
-duty three-prong extension cord rated for
at least 15 amps.
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2-43 Exit Lighting
With exit lighting, the interior lamps will come on when
you remove the key from the ignition. If the DOME
OVERRIDE button is in the ªoutº position, these lights
will stay on for a short period of time and then will
go out.
Front Reading Lamps
Press the button near each lamp on the overhead console
to turn the reading lamps on and off. The lamps can be
swiveled to point in the desired direction.
If you have the mini console, press the lens on each
lamp to turn it on or off.
Dome Lamps
The dome lamps will come on when you open the doors.
You can also turn the dome lamps on by rotating the
thumbwheel, located next to the parking/headlamps
knob, all the way up. In this position, the dome lamps
will remain on whether the doors are opened or closed.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 to remain off. To turn the lamps off, press the
button once into the ªinº position. 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. This will
override the illuminated entry feature, unless you use
your keyless entry transmitter to unlock the vehicle.
Battery Run-Down 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.
If the battery run
-down protection shuts off the interior
lamps, it may be necessary to do one of the following to
return to normal operation:

Shut off all lamps and close all doors, or

Turn the ignition key to RUN.
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5-4
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren't touching
each other. If they are, it could cause a ground
connection you don't want. You wouldn't be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on each vehicle. Put an
automatic transmission in PARK (P) or a manual
transmission in NEUTRAL (N) before setting the
parking brake.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or the accessory power outlets. Turn off all
lamps that aren't needed as well as radios. This will
avoid sparks and help save both batteries. In
addition, it could save your radio!
NOTICE:
If you leave your radio on, it could be badly
damaged. The repair wouldn't be covered by
your warranty.
4. Open both hoods and locate the batteries. Find the
positive (+) and negative (
-) terminals on each battery.
CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing this,
and some have been blinded. Use a flashlight if
you need more light.
Be sure the battery has enough water. You don't
need to add water to the ACDelco Freedom

battery installed in every new GM vehicle. But if
a battery has filler caps, be sure the right amount
of fluid is there. If it is low, add water to take care
of that first. If you don't, explosive gas could
be present.
Battery fluid contains acid that can burn you.
Don't get it on you. If you accidentally get it in
your eyes or on your skin, flush the place with
water and get medical help immediately.
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5-8
Engine Overheating
You will find a coolant temperature gage on your
vehicle's instrument panel. See ªGagesº in the Index.
If Steam Is Coming From Your Engine
CAUTION:
Steam from an overheated engine can burn you
badly, even if you just open the hood. Stay away
from the engine if you see or hear steam coming
from it. Just turn it off and get everyone away
from the vehicle until it cools down. Wait until
there is no sign of steam or coolant before you
open the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch fire. You or
others could be badly burned. Stop your engine if
it overheats, and get out of the vehicle until the
engine is cool.
NOTICE:
If your engine catches fire because you keep
driving with no coolant, your vehicle can be
badly damaged. The costly repairs would not be
covered by your warranty.
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5-9 If No Steam Is Coming From Your Engine
If you get an engine overheat warning but see or hear no
steam, the problem may not be too serious. Sometimes
the engine can get a little too hot when you:

Climb a long hill on a hot day.

Stop after high
-speed driving.

Idle for long periods in traffic.

Tow a trailer. See ªDriving on Gradesº in the Index.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. If your air conditioner is on, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
3. If you're in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
-- DRIVE (D) or THIRD (3).If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning doesn't come back on, you can
drive normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there's still no sign of steam, push down the
accelerator until the engine speed is about twice as fast
as normal idle speed for at least three minutes while
you're parked. If you still have the warning, turn off the
engine and get everyone out of the vehicle until it
cools down.
You may decide not to lift the hood but to get service
help right away.
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6-4
If your vehicle is certified to meet California Emission
Standards (indicated on the underhood emission control
label), it is designed to operate on fuels that meet
California specifications. If such fuels are not available
in states adopting California emissions standards, your
vehicle will operate satisfactorily on fuels meeting
federal specifications, but emission control system
performance may be affected. The malfunction indicator
lamp on your instrument panel may turn on and/or your
vehicle may fail a smog
-check test. (See ªMalfunction
Indicator Lampº in the Index.) If this occurs, return to
your authorized GMC dealer for diagnosis to determine
the cause of failure. In the event it is determined that the
cause of the condition is the type of fuels used, repairs
may not be covered by your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane
-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask your service station operator whether or not
the fuel contains MMT. General Motors does not
recommend the use of such gasolines. If fuels containing
MMT are used, spark plug life may be reduced and your
emission control system performance may be affected.
The malfunction indicator lamp on your instrument
panel may turn on. If this occurs, return to your
authorized GMC dealer for service.To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent deposits from forming in your engine and fuel
system, allowing your emission control system to
function properly. Therefore, you should not have to add
anything to the fuel. In addition, gasolines containing
oxygenates, such as ethers and ethanol, and
reformulated gasolines may be available in your area to
contribute to clean air. General Motors recommends that
you use these gasolines, particularly if they comply with
the specifications described earlier.
NOTICE:
Your vehicle was not designed for fuel that
contains methanol. Don't use it. It can corrode
metal parts in your fuel system and also damage
plastic and rubber parts. That damage wouldn't
be covered under your warranty.
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6-8
Checking Things Under the Hood
CAUTION:
Things that burn can get on hot engine parts and
start a fire. These include liquids like gasoline,
oil, coolant, brake fluid, windshield washer and
other fluids, and plastic or rubber. You or others
could be burned. Be careful not to drop or spill
things that will burn onto a hot engine.
To open the hood, first pull
the handle inside the vehicle
on the lower driver's side of
the instrument panel.Then go to the front of the vehicle and release the
secondary hood release.
Lift the hood, release the hood prop from its retainer and
put the hood prop into the slot in the hood. You may
have a lamp that comes on when you lift the hood.
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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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