Page 2 of 452
Rear Axle
............................................. 331
Front Axle
............................................ 331
Noise Control System
........................... 332
Bulb Replacement
................................ 334
Windshield Wiper Blade
Replacement
..................................... 338
Tires
..................................................... 340
Appearance Care
.................................. 377
Vehicle Identification
............................. 386
Electrical System
.................................. 387
Capacities and Specifications
................ 393Maintenance Schedule
.............................. 395
Maintenance Schedule
.......................... 396
Customer Assistance Information
............. 417
Customer Assistance and
Information
........................................ 418
Reporting Safety Defects
...................... 436
Index
.......................................................... 439
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        Page 182 of 452
Oil Pressure Gage
The oil pressure gage shows the engine oil
pressure in psi (pounds per square inch) when the
engine is running. Canadian vehicles indicate
pressure in kPa (kilopascals).
Oil pressure may vary with engine speed, outside
temperature and oil viscosity, but readings
above the low pressure zone indicate the normal
operating range.A reading in the low pressure zone may be
caused by a dangerously low oil level or other
problem causing low oil pressure. Check your oil
as soon as possible.
{CAUTION:
Do not keep driving if the oil pressure is
low. If you do, your engine can become so
hot that it catches  re. You or others could
be burned. Check your oil as soon as
possible and have your vehicle serviced.
Notice:Lack of proper engine oil maintenance
may damage the engine. The repairs would
not be covered by your warranty. Always follow
the maintenance schedule in this manual for
changing engine oil.
United StatesCanada
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        Page 183 of 452

Change Engine Oil Light
This light is displayed
when your vehicle
needs to be serviced.
If your vehicle has a V8 engine and this light is
flashing, it indicates that the oil level is low.
When this light is on steady, your vehicle needs to
be serviced. SeeScheduled Maintenance
(Gasoline Engine) on page 399for more
information.
Once the engine oil has been changed, the
change engine oil light must be reset. Until it is
reset, the light will stay on for a while each time the
engine is started. For more information on
resetting the system, see “How to Reset the
Engine Oil Life System” underEngine Oil
Life System (Gasoline Engine) on page 300.
Security Light
The light will stay on until the engine starts. If the
light flashes, the Passlock®System has entered
a tamper mode. If the vehicle fails to start,
seePasslock
®on page 119.
If the light comes on continuously while driving
and stays on, there may be a problem with
the Passlock
®System. Your vehicle will not be
protected by Passlock®, and you should see your
GM dealer.
United StatesCanada
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        Page 282 of 452

Maintenance When Trailer Towing
Your vehicle will need service more often when
you’re pulling a trailer. See the Maintenance
Schedule for more on this. Things that are
especially important in trailer operation are
automatic transmission fluid (don’t overfill), engine
oil, axle lubricant, belt, cooling system and brake
system. Each of these is covered in this manual,
and the Index will help you find them quickly.
If you’re trailering, it’s a good idea to review these
sections before you start your trip.
Check periodically to see that all hitch nuts and
bolts are tight.
Trailer Wiring Harness
The optional heavy-duty trailer wiring package
includes a seven-wire harness assembly at
the rear of the vehicle and a four-wire
harness assembly under the left hand side
of the instrument panel. The seven-wire
harness assembly is taped together and
located in a frame pocket at the driver side
rear left corner of the frame.The seven-wire harness includes a 30-amp feed
wire. Both harnesses come without connectors and
should be wired by a qualified electrical technician.
The technician can use the following color code
chart when connecting the wiring harness to
your trailer and trailer brake controller.
Seven-Wire Harness
•Light Green: Back-up lamps
•Brown: Parking lamps
•Yellow: Left stoplamp and turn signal
•Dark Green: Right stoplamp and turn signal
•Dark Blue: Use for electric trailer brakes
•Red/Black Stripe: Trailer accessory
•White (heavy gage): Ground wire
Four-Wire Harness (Trailer Brake Controller)
•Black: Ground
•Red/White Stripe: Fused Battery
•Dark Blue: Trailer Brake Feed
•Light Blue: Fused Stoplamp/CHMSL
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        Page 302 of 452

Engine Air Cleaner/Filter
The engine air cleaner/filter is located near the
center of the engine compartment. SeeEngine
Compartment Overview on page 296for more
information on location.
When to Inspect the Engine Air
Cleaner/Filter
Inspect the air cleaner/filter at the MaintenanceII
intervals and replace it at the first oil change
after each 50,000 mile (85 000 km) interval. See
Scheduled Maintenance (Gasoline Engine) on
page 399for more information. If you are driving
in dusty/dirty conditions, inspect the filter at
each engine oil change.
How to Inspect the Engine Air
Cleaner/Filter
To inspect the air cleaner/filter, remove the filter
from the vehicle and lightly shake the filter to
release loose dust and dirt. If the filter remains
caked with dirt, a new filter is required. Never use
compressed air to clean the filter.
To inspect or replace the engine air cleaner/filter,
do the following:
1. Unhook the retainer clips and remove
the cover.
2. Lift the filter out of the engine air cleaner/filter
housing. Care should be taken to dislodge as
little dirt as possible.
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        Page 306 of 452

How to Add Automatic
Transmission Fluid
Refer to the Maintenance Schedule to determine
what kind of transmission fluid to use. See
Recommended Fluids and Lubricants on page 409.
Using a funnel, add fluid down the transmission
dipstick tube only after checking the transmission
fluid while it is hot. A cold check is used only
as a reference. If the fluid level is low, add only
enough of the proper fluid to bring the level up to
the HOT area for a hot check. It does not take
much fluid, generally less than one pint (0.5 L). Do
not overfill.
Notice:Use of the incorrect automatic
transmission  uid may damage your vehicle,
and the damages may not be covered by
your warranty. Always use the automatic
transmission  uid listed inRecommended
Fluids and Lubricants on page 409.
•After adding fluid, recheck the fluid level as
described under “How to Check Automatic
Transmission Fluid,” earlier in this section.
•When the correct fluid level is obtained, push
the dipstick back in all the way; then flip the
handle down to lock the dipstick in place.
Engine Coolant
The cooling system in your vehicle is filled with
DEX-COOL®engine coolant. This coolant is
designed to remain in your vehicle for five years or
150,000 miles (240 000 km), whichever occurs first,
if you add only DEX-COOL
®extended life coolant.
The following explains your cooling system and
how to add coolant when it is low. If you have a
problem with engine overheating, seeEngine
Overheating on page 309.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
•Give freezing protection down to
−34°F (−37°C).
•Give boiling protection up to 265°F (129°C).
•Protect against rust and corrosion.
•Help keep the proper engine temperature.
•Let the warning lights and gages work as
they should.
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        Page 320 of 452

So, it is not a good idea to top off your brake fluid.
Adding brake fluid will not correct a leak. If you
add fluid when your linings are worn, then you will
have too much fluid when you get new brake
linings. You should add or remove brake fluid, as
necessary, only when work is done on the
brake hydraulic system.
{CAUTION:
If you have too much brake  uid, it can
spill on the engine and/or fuel operated
heater parts, if equipped. If your vehicle
has a diesel engine and a fuel operated
heater, see “Fuel Operated Heater (FOH)”
in the diesel engine supplement. The  uid
will burn if the engine is hot enough. You
or others could be burned, and your
vehicle could be damaged. Add brake
 uid only when work is done on the brake
hydraulic system. See “Checking Brake
Fluid” in this section.Refer to the Maintenance Schedule to determine
when to check your brake fluid. SeeScheduled
Maintenance (Gasoline Engine) on page 399.
Checking Brake Fluid
You can check the brake fluid without taking off
the cap.
Look at the brake fluid
reservoir. The fluid level
should be above
MIN. If it is not, have
your brake system
checked to see if
there is a leak.
After work is done on the brake hydraulic system,
make sure the level is above the MIN but not
over the MAX mark.
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        Page 330 of 452
All-Wheel Drive
Lubricant checks in this section also apply to
these vehicles. However, there are two additional
systems that need lubrication.
Transfer Case
When to Check Lubricant
Refer to the Maintenance Schedule to determine
how often to check the lubricant. SeeScheduled
Maintenance (Gasoline Engine) on page 399.
How to Check Lubricant
To get an accurate reading, the vehicle should be
on a level surface.If the level is below the bottom of the filler plug
hole, you’ll need to add some lubricant. Add
enough lubricant to raise the level to the bottom of
the filler plug hole. Use care not to overtighten
the plug.
What to Use
Refer to the Maintenance Schedule to determine
what kind of lubricant to use. SeeRecommended
Fluids and Lubricants on page 409.
330