Page 568 of 680

When It Is Time for New Tires
One way to tell when it
is time for new tires is
to check the treadwear
indicators, which will
appear when your tires
have only 1/16 inch
(1.6 mm) or less of tread
remaining. Some
commercial truck tires
may not have treadwear
indicators.
You need a new tire if any of the following
statements are true:
You can see the indicators at three or more
places around the tire.
You can see cord or fabric showing through
the tire’s rubber.
The tread or sidewall is cracked, cut or
snagged deep enough to show cord or fabric.
The tire has a bump, bulge, or split.
The tire has a puncture, cut, or other damage
that cannot be repaired well because of the
size or location of the damage.
Buying New Tires
GM has developed and matched speci c tires for
your vehicle. The original equipment tires
installed on your vehicle, when it was new, were
designed to meet General Motors Tire
Performance Criteria Speci cation (TPC spec)
system rating. If you need replacement tires, GM
strongly recommends that you get tires with
the same TPC Spec rating. This way, your vehicle
will continue to have tires that are designed to
give the same performance and vehicle safety,
during normal use, as the original tires.
GM’s exclusive TPC Spec system considers over
a dozen critical speci cations that impact the
overall performance of your vehicle, including
brake system performance, ride and handling,
traction control, and tire pressure monitoring
performance. GM’s TPC Spec number is molded
onto the tire’s sidewall by the tire manufacturer.
If the tires have an all-season tread design,
the TPC spec number will be followed by an MS
for mud and snow. SeeTire Sidewall Labeling
on page 551for additional information.
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Your vehicle’s original equipment tires are listed
on the Tire and Loading Information Label.
This label is attached to the vehicle’s center pillar
(B-pillar). SeeLoading Your Vehicle on page 425,
for more information about the Tire and Loading
Information Label and its location on your vehicle.
Different Size Tires and Wheels
If you add wheels or tires that are a different size
than your original equipment wheels and tires,
this could affect the way your vehicle performs,
including its braking, ride and handling
characteristics, stability, and resistance to rollover.
Additionally, if your vehicle has electronic
systems such as anti-lock brakes, rollover airbags,
traction control, and electronic stability control,
the performance of these systems can be affected.
{CAUTION:
If you add different sized wheels, your
vehicle may not provide an acceptable
level of performance and safety if tires not
recommended for those wheels are
selected. You may increase the chance
that you will crash and suffer serious
injury. Only use GM speci c wheel and
tire systems developed for your vehicle,
and have them properly installed by a GM
certi ed technician.
SeeBuying New Tires on page 568and
Accessories and Modi cations on page 486for
additional information.
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Page 573 of 680

Wheel Replacement
Replace any wheel that is bent, cracked, or badly
rusted or corroded. If wheel nuts keep coming
loose, the wheel, wheel bolts and wheel nuts
should be replaced. If the wheel leaks air, replace
it (except some aluminum wheels, which can
sometimes be repaired). See your dealer if any of
these conditions exist.
Your dealer will know the kind of wheel you need.
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 or wheel nuts, replace them only with
new GM original equipment parts. This way, you
will be sure to have the right wheel, wheel
bolts and wheel nuts 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.
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Page 574 of 680

Whenever a wheel, wheel bolt or wheel nut is
replaced on a dual wheel setup, check the wheel
nut torque after 100, 1,000 and 6,000 miles
(160, 1 600 and 10 000 km) of driving. For proper
torque, see “Wheel Nut Torque” underCapacities
and Speci cations on page 616.
SeeChanging a Flat Tire on page 576for 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.
Tire Chains
{CAUTION:
If your vehicle has dual wheels or
P265/65R18, P275/55R20 or LT265/70R17
size tires, do not use tire chains. They can
damage your vehicle because there is not
enough clearance. Tire chains used on a
vehicle without the proper amount of
clearance can cause damage to the
brakes, suspension, or other vehicle
parts. The area damaged by the tire
chains could cause you to lose control of
your vehicle and you or others may be
injured in a crash.
CAUTION: (Continued)
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Page 576 of 680

If a Tire Goes Flat
It is unusual for a tire to blowout while you are
driving, especially if you maintain your vehicle’s
tires properly. If air goes out of a tire, it is
much more likely to leak out slowly. But if you
should ever have a blowout, here are a few tips
about what to expect and what to do:
If a front tire fails, the at tire will create a drag
that pulls the vehicle toward that side. Take your
foot off the accelerator pedal and grip the
steering wheel rmly. Steer to maintain lane
position, and then gently brake to a stop well out
of the traffic lane.
A rear blowout, particularly on a curve, acts much
like a skid and may require the same correction
you would use in a skid. In any rear blowout
remove your foot from the accelerator pedal. Get
the vehicle under control by steering the way
you want the vehicle to go. It may be very bumpy
and noisy, but you can still steer. Gently brake
to a stop, well off the road if possible.{CAUTION:
Lifting a vehicle and getting under it to do
maintenance or repairs is dangerous
without the appropriate safety equipment
and training. The jack provided with your
vehicle is designed only for changing a
at tire. If it is used for anything else, you
or others could be badly injured or killed
if the vehicle slips off the jack. Use the
jack provided with your vehicle only for
changing a at tire.
If a tire goes at, the next part shows how to use
the jacking equipment to change a at tire safely.
Changing a Flat Tire
If a tire goes at, avoid further tire and wheel
damage by driving slowly to a level place. Turn on
your hazard warning ashers. SeeHazard
Warning Flashers on page 211for more
information.
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Page 577 of 680

{CAUTION:
Changing a tire can be dangerous. The
vehicle can slip off the jack and roll over
or fall on you or other people. You and
they could be badly injured or even killed.
Find a level place to change your tire. To
help prevent the vehicle from moving:
1. Set the parking brake rmly.
2. Put the shift lever in PARK (P).
3. If you have a four-wheel-drive vehicle,
be sure the transfer case is in a drive
gear – not in NEUTRAL.
4. Turn off the engine and do not restart
while the vehicle is raised.
5. Do not allow passengers to remain in
the vehicle.
CAUTION: (Continued)
CAUTION: (Continued)
To be even more certain the vehicle will
not move, put blocks at the front and rear
of the tire farthest away from the one
being changed. That would be the tire on
the other side, at the opposite end of the
vehicle.
When your vehicle has a at tire, use the following
example as a guide to assist you in the placement
of the wheel blocks.
The following information will tell you next how to
use the jack and change a tire.
577
Page 588 of 680

{CAUTION:
Incorrect wheel nuts or improperly
tightened wheel nuts can cause the wheel
to come loose and even come off. This
could lead to an accident. Be sure to use
the correct wheel nuts. If you have to
replace them, be sure to get new GM
original equipment wheel nuts. Stop
somewhere as soon as you can and have
the nuts tightened with a torque wrench to
the proper torque speci cation. See
Capacities and Specifications on page 616
for wheel nut torque speci cation.
Notice:Improperly tightened wheel nuts can
lead to brake pulsation and rotor damage.
To avoid expensive brake repairs, evenly
tighten the wheel nuts in the proper sequence
and to the proper torque speci cation. See
Capacities and Specifications on page 616for
the wheel nut torque speci cation.11. Tighten the nuts rmly in a crisscross
sequence as shown by turning the wheel
wrench clockwise.
When you reinstall the regular wheel and tire, you
must also reinstall either the center cap, or
bolt-on hub cap, depending on what your vehicle
is equipped with. For center caps, place the
cap on the wheel and tap it into place until it seats
ush with the wheel. The cap only goes on one
way. Be sure to line up the tab on the center cap
with the indentation on the wheel. For bolt-on
hub caps, align the plastic nut caps with the wheel
nuts and then tighten by hand. Then use the
wheel wrench to tighten.
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Page 611 of 680
Center Instrument Panel Fuse Block
The center instrument panel fuse block is
located underneath the instrument panel, to the
left of the steering column.
Top View
Harness
ConnectorUsage
BODY 2 Body Harness Connector 2
BODY 1 Body Harness Connector 1
BODY 3 Body Harness Connector 3
HEADLINER 3 Headliner Harness Connector 3
HEADLINER 2 Headliner Harness Connector 2
HEADLINER 1 Headliner Harness Connector 1
BRAKE
CLUTCHBrake Clutch Harness Connector
SEO/UPFITTERSpecial Equipment Option Up tter
Harness Connector
Circuit Breaker Usage
CB1Passenger’s Side Power Window
Circuit Breaker
CB2 Passenger’s Seat Circuit Breaker
CB3 Driver’s Seat Circuit Breaker
CB4 Not Used
611