wiring GMC ENVOY 2002 Owner's Manual

2-13
To replace the battery in the remote keyless
entry transmitter:
1. Insert a thin coin in the slot between the covers
of the transmitter housing. Gently pry the
transmitter apart.
2. Remove and replace the battery with a three
-volt
CR2032 or equivalent battery, positive (+)
side down.
3. Align the covers and snap them together.
4. Check the operation of the transmitter.
Liftgate/Liftglass
CAUTION:
It can be dangerous to drive with the liftgate or
liftglass open because carbon monoxide (CO) gas
can come into your vehicle. You can't see or smell
CO. It can cause unconsciousness and even death.
If you must drive with the liftgate or liftglass
open or if electrical wiring or other cable
connections must pass through the seal between
the body and the liftgate or liftglass:

Make sure all other windows are shut.

Turn the fan on your heating or cooling
system to its highest speed with the setting
on panel or bi
-level with recirculation off.
That will force outside air into your vehicle.
See ªComfort Controlsº in the Index.

If you have air outlets on or under the
instrument panel, open them all the way.
See ªEngine Exhaustº in the Index.

2-39
If a bulb is burned out, replace it to help avoid an
accident. If the arrows don't go on at all when you
signal a turn, check the fuse (see ªFuses and Circuit
Breakersº in the Index) and for burned
-out bulbs.
If you have a trailer towing option with added wiring for
the trailer lamps, a different turn signal flasher is used.
With this flasher installed, the signal indicator will flash
even if a turn signal bulb is burned out. Check the front
and rear turn signal lamps regularly to make sure they
are working.
Turn Signal On Chime
If your turn signal is left on for more than 3/4 of a mile
(1.2 km), a chime will sound at each flash of the turn
signal. To turn off the chime, move the turn signal lever
to the off position.
Headlamp High/Low-Beam Changer
To change the headlamps from low to high beam, push
the lever toward the instrument panel. To return to
low
-beam headlamps, pull the multifunction lever
toward you. Then release it.
When the high beams are
on, this indicator light on
the instrument panel cluster
will also be on.

2-77
Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows the air bag symbol. The system
checks the air bag's electrical system for malfunctions.
The light tells you if there is an electrical problem. The
system check includes the air bag sensors, the air bag
modules, the wiring and the crash sensing and
diagnostic module. For more information on the air bag
system, see ªAir Bagº in the Index.
This light will come on
when you start your vehicle,
and it will flash for a few
seconds. Then the light
should go out. This means
the system is ready.
If the air bag readiness light stays on after you start the
vehicle or comes on when you are driving, your air bag
system may not work properly. Have your vehicle
serviced right away.
CAUTION:
If the air bag readiness light stays on after you
start your vehicle, it means the air bag system
may not be working properly. The air bags in
your vehicle may not inflate in a crash, or they
could even inflate without a crash. To help avoid
injury to yourself or others, have your vehicle
serviced right away if the air bag readiness light
stays on after you start your vehicle.
The air bag readiness light should flash for a few
seconds when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.

4-60 Trailer Wiring Harness
Your vehicle is equipped with the seven-wire trailer
towing harness. This harness has a seven
-pin universal
heavy
-duty trailer connector that is attached to a bracket
on the hitch platform. The seven
-wire harness contains
the following trailer circuits:

Yellow: Left Stop/Turn Signal

Dark Green: Right Stop/Turn Signal

Brown: Running Lamps

White: Ground

Light Green: Back
-up Lamps

Red: Battery Feed

Dark Blue: Electric Brakes
If you need to tow a light
-duty trailer with a standard
four
-way round pin connector, an adapter connector is
available from your dealer.
Your vehicle is also equipped with wiring for an electric
trailer brake controller. These wires are located inside
the vehicle on the driver's side under the instrument
panel. These wires should be connected to an electric
trailer brake controller by your dealer or a qualified
service center.

6-34 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
1. Open the hood.
2. Lift the inner quick release clips.
3. Pull the headlamp assembly away from the vehicle.
4. Remove the cover from the headlamp bulb.
5. Disconnect the wiring harness.
6. Remove the headlamp bulb by turning the socket
counterclockwise.
7. To install the replacement bulb, reverse
Steps 1 through 6.
Front Turn Signals and Sidemarker Lamps
Follow the same procedure listed for headlamp removal
earlier in this section. Replace the turn signal or
sidemarker bulb instead.
Taillamps and Rear Turn Signals
1. Open the liftgate.
2. Remove the two screws
from the lamp assembly.
3. Pull the assembly away from the vehicle.

6-35
4. Unclip the wiring harness (A) and remove the
three socket retaining screws (B).
5. Remove the socket by releasing the retaining tabs.
6. Holding the socket, pull the bulb to release it from
the socket.
7. Push the new bulb into the socket until it clicks.
8. Reinstall the socket and screws.
9. Reconnect the wiring harness.
10. Reinstall the lamp assembly and tighten the screws.
11. Close the liftgate.

6-56
Electrical System
Add-On Electrical Equipment
NOTICE:
Don't add anything electrical to your vehicle
unless you check with your dealer first. Some
electrical equipment can damage your vehicle
and the damage wouldn't be covered by your
warranty. Some add
-on electrical equipment
can keep other components from working as
they should.
Your vehicle has an air bag system. Before attempting to
add anything electrical to your vehicle, see ªServicing
Your Air Bag
-Equipped Vehicleº in the Index.
Headlamps
The headlamp wiring is protected by four fuses. An
electrical overload will cause a lamp to go on and off.
If this happens, have your headlamp wiring checked
right away.
Windshield Wipers
The windshield wiper motor is protected by a circuit
breaker and a fuse. If the motor overheats due to heavy
snow or ice, the wiper will stop until the motor cools. If
the overload is caused by some electrical problem, be
sure to get it fixed.
Power Windows and Other Power Options
Circuit breakers protect the power windows and other
power accessories. When the current load is too heavy,
the circuit breaker opens and closes, protecting the
circuit until the problem is fixed or goes away.

6-57 Fuses and Circuit Breakers
The wiring circuits in your vehicle are protected from
short circuits by a combination of fuses and circuit
breakers. This greatly reduces the chance of fires caused
by electrical problems.
Look at the silver
-colored band inside the fuse. If the
band is broken or melted, replace the fuse. Be sure you
replace a bad fuse with a new one of the identical size
and rating.
If you ever have a problem on the road and don't have
a spare fuse, you can borrow one that has the same
amperage. Just pick some feature of your vehicle that
you can get along without
-- like the radio or cigarette
lighter
-- and use its fuse, if it is the correct amperage.
Replace it as soon as you can.
Air Conditioning Refrigerant Capacity
If you do your own service work, you'll need the proper
service manual. See ªDoing Your Own Service Workº in
the Index for additional information. It is recommended
that service work on your air conditioning system be
performed by a qualified technician.Engine Compartment Fuse Block
The fuse block is located under the hood in the engine
compartment on the driver's side of the vehicle. See
ªEngine Compartment Overviewº in the Index for more
information on location.
Remove the cover by turning the fastener
counterclockwise. To reinstall the fuse panel cover, push
in and turn the fastener clockwise.