2008 GMC ENVOY wiring

Servicing Your Airbag-Equipped
Vehicle
Airbags affect how your vehicle should be serviced.
There are parts of the airbag system in several places
around your vehicle. Your dealer/retailer and the service
manual have information about servicing your vehicle
and the airbag system. To purchase a service manual,
seeService Publications Ordering Information on
page 7-16.
{CAUTION:
For up to 10 seconds after the ignition is
turned off and the battery is disconnected, an
airbag can still inate during improper service.
You can be injured if you are close to an airbag
when it inates. Avoid yellow connectors. They
are probably part of the airbag system. Be sure
to follow proper service procedures, and make
sure the person performing work for you is
qualied to do so.
Adding Equipment to Your
Airbag-Equipped Vehicle
Q:Is there anything I might add to or change
about the vehicle that could keep the airbags
from working properly?
A:Yes. If you add things that change your vehicle’s
frame, bumper system, height, front end or side
sheet metal, they may keep the airbag system from
working properly. Changing or moving any parts
of the front seats, safety belts, the airbag sensing
and diagnostic module, steering wheel, instrument
panel, roof-rail airbag modules, ceiling headliner
or pillar garnish trim, rearview mirror, front sensors,
rollover sensor module, or airbag wiring can
affect the operation of the airbag system.
In addition, your vehicle has a passenger sensing
system for the right front passenger’s position,
which includes sensors that are part of the
passenger’s seat. The passenger sensing
system may not operate properly if the original
seat trim is replaced with non-GM covers,
upholstery or trim, or with GM covers, upholstery
or trim designed for a different vehicle.
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Any object, such as an aftermarket seat heater or a
comfort enhancing pad or device, installed under or
on top of the seat fabric, could also interfere with
the operation of the passenger sensing system.
This could either prevent proper deployment of the
passenger airbag(s) or prevent the passenger
sensing system from properly turning off the
passenger airbag(s). SeePassenger Sensing
System on page 1-61.
If you have any questions about this, you should
contact Customer Assistance before you modify
your vehicle. The phone numbers and addresses
for Customer Assistance are in Step Two of
the Customer Satisfaction Procedure in this manual.
SeeCustomer Satisfaction Procedure on page 7-2.
If your vehicle has rollover roof-rail airbags, see
Different Size Tires and Wheels on page 5-76
for additional important information.Q:Because I have a disability, I have to get my
vehicle modied. How can I nd out whether
this will affect my airbag system?
A:If you have questions, call Customer Assistance.
The phone numbers and addresses for Customer
Assistance are in Step Two of the Customer
Satisfaction Procedure in this manual. See
Customer Satisfaction Procedure on page 7-2.
In addition, your dealer/retailer and the service manual
have information about the location of the airbag sensors,
sensing and diagnostic module and airbag wiring.
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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 cannot see
or smell CO. It can cause unconsciousness and
even death. If you must drive with the liftgate
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 climate control system
to its highest speed and select the control
setting that will force outside air into your
vehicle. See “Climate Control System” in
the Index.
If you have air outlets on or under the
instrument panel, open them all the way.
SeeEngine Exhaust on page 2-37.
Liftgate Release
To unlock the liftgate, use the power door lock switch
or the remote keyless entry transmitter. SeeRemote
Keyless Entry (RKE) System Operation on page 2-5.
The liftglass will also unlock when the liftgate is
unlocked.
Press the button on the liftglass to open it. To open the
entire liftgate, lift the handle located in the center of
the liftgate. When the liftgate is opened, the liftglass
will lock after a short delay.
Emergency Release for Opening
Liftgate
1. Remove the trim plug, located on the inside of the
liftgate in the center, to expose the access hole in
the trim panel.
2. Use a tool to reach through the access hole in the
trim panel.
3. Pry the left release lever up to the unlock position.
Pry the right release lever up to unlatch the liftgate.
4. Reinstall the trim plug.
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Turn Signal/Multifunction Lever
The lever on the left side of the steering column
includes the following:
GTurn and Lane Change Signals
23Headlamp High/Low-Beam Changer
Flash-to-Pass Feature
NWindshield Wipers
JWindshield Washer
ICruise Control
Turn and Lane-Change Signals
The turn signal has two upward and two downward
positions.
To signal a turn, move the lever all the way up or down.
When the turn is nished, the lever returns automatically.
An arrow on the instrument
panel cluster ashes in the
direction of the turn or
lane change.
To signal a lane change, raise or lower the lever until
the arrow starts to ash. Hold it there until your lane
change is completed. The lever returns by itself when
released.
If the arrows ash more quickly than normal, a signal
bulb could be burned out. Replace the bulb. If the arrows
do not go on at all when you signal a turn, check the
fuse. SeeFuses and Circuit Breakers on page 5-110
and check for burned-out bulbs.
If you have a trailer towing option with added wiring for
the trailer lamps, a turn signal asher is used. With this
asher installed, the signal indicator ashes even if a turn
signal bulb is burned out. Check the front and rear turn
signal lamps regularly to make sure they are working.
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This chime and light is repeated if the driver remains
unbuckled and the vehicle is in motion. If the driver’s belt
is already buckled, neither the chime nor the light will
come on.
Passenger Safety Belt Reminder Light
Several seconds after the engine is started, a chime will
sound for several seconds to remind the front passenger
to buckle their safety belt. This would only occur if the
passenger airbag is enabled. SeePassenger Sensing
System on page 1-61for more information. The
passenger safety belt light, located on the instrument
panel, will come on and stay on for several seconds and
then ash for several more.
This chime and light are
repeated if the passenger
remains unbuckled and
the vehicle is in motion.
If the passenger’s safety belt is buckled, neither the
chime nor the light will come on.
Airbag Readiness Light
There is an airbag readiness light on the instrument panel
cluster, which shows the airbag symbol. The system
checks the airbag’s electrical system for malfunctions.
The light tells you if there is an electrical problem.
The system check includes the airbag sensor, the
pretensioners, the airbag modules, the wiring and
the crash sensing and diagnostic module. For more
information on the airbag system, seeAirbag System
on page 1-53.
This light will come on
when you start your
vehicle, and it will ash
for a few seconds. The
light should go out and
the system is ready.
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Trailer Wiring Harness
Your vehicle may be equipped with the seven-wire
trailer towing harness. This harness has a seven-pin
universal heavy-duty trailer connector (if equipped with
the trailering package) that is attached to a bracket
on the hitch platform. If your vehicle is not equipped with
the heavy-duty trailer connector, you may purchase
one from your dealer.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.
If you are charging a remote (non-vehicle) battery, turn
on the headlamps to boost the vehicle system voltage
and properly charge the battery.
Your vehicle may also be 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 qualied service center.
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4. Unclip the wiring harness (A) and remove the
three socket retaining screws (B).5. Remove the socket plate.
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 plate and tighten the
three screws.
9. Reconnect the wiring harness.
10. Reinstall the taillamp assembly by lining up the
locator pins with the retainers in the body of the
vehicle.
11. Reinstall the two screws and tighten.
12. Close the liftgate.
5-52

Electrical System
Add-On Electrical Equipment
Notice:Do not add anything electrical to your
vehicle unless you check with your dealer/retailer
rst. Some electrical equipment can damage your
vehicle and the damage would not be covered by
your warranty. Some add-on electrical equipment can
keep other components from working as they should.
Add-on equipment can drain your vehicle’s battery, even
if your vehicle is not operating.
Your vehicle has an airbag system. Before attempting to
add anything electrical to your vehicle, seeServicing
Your Airbag-Equipped Vehicle on page 1-66.
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 Wiper Fuses
The windshield wiper motor is protected by a circuit
breaker and a fuse. If the motor overheats due to heavy
snow, etc., the wiper will stop until the motor cools.
If the overload is caused by some electrical problem,
have it xed.
Power Windows and Other Power
Options
Circuit breakers in the fuse block 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 xed or
goes away.
5-109