2008 GMC ENVOY headlamp

What to Use
To determine what kind of lubricant to use, see
Recommended Fluids and Lubricants on page 6-12.
Headlamp Aiming
Headlamp aim has been preset at the factory and
should need no further adjustment.
However, if your vehicle is damaged in a crash, the
headlamp aim may be affected. Aim adjustment to the
low-beam headlamps may be necessary if oncoming
drivers ash their high-beam headlamps at you
(for vertical aim).
If the headlamps need to be re-aimed, it is
recommended that you take the vehicle to your
dealer/retailer for service.
Bulb Replacement
For the proper type of replacement bulbs, see
Replacement Bulbs on page 5-54.
For any bulb changing procedure not listed in this
section, contact your dealer/retailer.
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.
5-49

Headlamps
To replace one of these bulbs:
1. Open the hood.Hood Release on page 5-11for
more information.
2. Lift the two headlamp retaining clips.
3. Pull the headlamp assembly away from the vehicle
to access the electrical connectors.4. Remove the cover from the headlamp bulb.
5. Remove the bulb socket that needs to be replaced
by turning it counterclockwise.
6. Disconnect the electrical connector from the
old bulb.
7. Plug the electrical connector into the new bulb
using care not to touch the glass with your
ngers.
8. Install the new bulb into the socket and turn it
clockwise to secure.
9. Reinstall by reversing Steps 1 through 6.
10. Press down on the headlamp retaining clips to
secure the headlamp assembly.
5-50

Front Turn Signal, Sidemarker and
Parking Lamps
To replace one of these bulbs:
1. Follow Steps 1 through 3 underHeadlamps on
page 5-50to access the front turn signal,
sidemarker or parking lamp.
2. Turn the bulb socket counterclockwise and remove
it from the lamp assembly.
3. Holding the socket, pull the old bulb to release it
from the socket.
4. Push the new bulb into the socket until it clicks.
5. Insert the bulb socket into the lamp assembly and
turn it clockwise to secure.
6. Reinstall the headlamp assembly by lining up the
headlamp assembly with the slots in the headlamp
retaining clips.
7. Press down on the headlamp retaining clips to
secure the headlamp assembly.
Taillamps, Turn Signal, and
Stoplamps
To replace a stoplamp/taillamp or turn signal bulb:
1. Open the liftgate. SeeLiftgate/Liftglass on
page 2-12for more information.
2. Remove the
two screws from the
taillamp assembly.
3. Pull the assembly away from the vehicle.
5-51

Replacement Bulbs
Exterior Lamp Bulb Number
Back-up Lamps/Rear Turn Signal
Lamp, Stoplamp, and Taillamp3157
Front Sidemarker Lamps 194
Front Turn Signal Lamps 3457
License Plate Lamp W5W
High-Beam Headlamps 9005 HB3
Low-Beam Headlamps 9006 HB4
For replacement bulbs not listed here, contact your
dealer/retailer.
Windshield Wiper Blade
Replacement
Windshield wiper blades should be inspected for wear
or cracking. SeeScheduled Maintenance on page 6-4.
Allowing the wiper blade arm to touch the windshield
when no wiper blade is installed could damage the
windshield. Any damage that occurs would notbe covered by your warranty. Do not allow the wiper
blade arm to touch 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 TabD. Blade Pivot
E. Hook Slot
F. Arm Hook
2. Press down on the blade assembly pivot locking
tab. Pull down on the blade assembly to release it
from the wiper arm hook.
5-54

TPMS Sensor Matching Process
Each TPMS sensor has a unique identication code.
Any time you rotate your vehicle’s tires or replace one or
more of the TPMS sensors, the identication codes will
need to be matched to the new tire/wheel position. The
sensors are matched to the tire/wheel positions in the
following order: driver side front tire, passenger side front
tire, passenger side rear tire, and driver side rear tire
using a TPMS diagnostic tool. See your dealer/retailer for
service.
The TPMS sensors can also be matched to each
tire/wheel position by increasing or decreasing the tire’s
air pressure. If increasing the tire’s air pressure, do not
exceed the maximum ination pressure indicated on the
tire’s sidewall.
To decrease air-pressure out of a tire you can use the
pointed end of the valve cap, a pencil-style air pressure
gage, or a key.
You have two minutes to match the rst tire/wheel
position, and ve minutes overall to match all four
tire/wheel positions. If it takes longer than two minutes, to
match the rst tire and wheel, or more than ve minutes
to match all four tire and wheel positions the matching
process stops and you need to start over.The TPMS sensor matching process is outlined below:
1. Set the parking brake.
2. Turn the ignition switch to ON/RUN with the
engine off.
3. Turn the headlamp control from off to parking lamps
four times within three seconds. A double horn chirp
will sound and the TPMS low tire warning light will
begin to ash. The double horn chirp and ashing
TPMS warning light indicate that the TPMS matching
process has started. The TPMS warning light should
continue ashing throughout the matching
procedure.
4. Start with the driver side front tire.
5. Remove the valve cap from the valve cap stem.
Activate the TPMS sensor by increasing or
decreasing the tire’s air pressure for 10 seconds,
then stop and listen for a single horn chirp. The
single horn chirp should sound within 15 seconds,
conrming that the sensor identication code has
been matched to this tire and wheel position. If you
do not hear the conrming single horn chirp, you will
need to start over with step number one.
6. Proceed to the passenger side front tire, and repeat
the procedure in Step 5.
7. Proceed to the passenger side rear tire, and repeat
the procedure in Step 5.
5-71

Each new wheel should have the same load-carrying
capacity, diameter, width, offset, and be mounted
the same way as the one it replaces.
If you need to replace any of your wheels, wheel bolts,
wheel nuts, or Tire Pressure Monitor System (TPMS)
sensors, replace them only with new GM original
equipment parts. This way, you will be sure to have the
right wheel, wheel bolts, wheel nuts, and TPMS sensors
for your vehicle.
{CAUTION:
Using the wrong replacement wheels, wheel
bolts, or wheel nuts on your vehicle can be
dangerous. It could affect the braking and
handling of your vehicle, make your tires lose
air and make you lose control. You could have
a collision in which you or others could be
injured. Always use the correct wheel, wheel
bolts, and wheel nuts for replacement.Notice:The wrong wheel can also cause problems
with bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper height,
vehicle ground clearance, and tire or tire chain
clearance to the body and chassis.
SeeChanging a Flat Tire on page 5-82for more
information.
Used Replacement Wheels
{CAUTION:
Putting a used wheel on your vehicle is
dangerous. You cannot know how it has been
used or how far it has been driven. It could fail
suddenly and cause a crash. If you have to
replace a wheel, use a new GM original
equipment wheel.
5-79

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

Fuses Usage
1Electrically-Controlled Air
Suspension
2Passenger Side High-Beam
HeadlampFuses Usage
3Passenger Side Low-Beam
Headlamp
4 Back-Up Trailer Lamps L6 Engine
5-111