
A reading in the low pressure zone may be caused by a
dangerously low oil level or other problem.
If you have a Caterpillar
®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
{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.
Low Oil Level Light
This light should come on
as a check, when you start
your engine. If the light
fails to come on, have it
repaired as soon as
possible so you will be
aware when the oil level
is low.
Vehicles equipped with Caterpillar
®diesel engines may
not have a low oil level light. In this case, the light
will neither come on as a check when you start your
engine, nor will it come on to indicate a low oil level.
If this light comes on and stays on, it means your engine
is low on oil. You need to check the oil level right
away. SeeEngine Oil (Caterpillar
®Diesel Engine) on
page 5-24orEngine Oil (DURAMAX®Diesel) on
page 5-24orEngine Oil (Gasoline Engine) on page 5-28
for further information.
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.
3-39

Change Engine Oil Light
The change engine oil light
should come on briefly as
a bulb check when you
start the engine. If the light
does not come on, have
it serviced.
If the change engine oil light comes on and stays on
after you start the engine, have the oil changed.
For additional information on when to change engine oil
for gasoline engines or DURAMAX
®diesel engines,
seeEngine Oil (Caterpillar®Diesel Engine) on page 5-24
orEngine Oil (DURAMAX®Diesel) on page 5-24or
Engine Oil (Gasoline Engine) on page 5-28and
Scheduled Maintenance on page 6-5. To reset the
change engine oil light, seeEngine Oil Life System
(Gasoline Engine) on page 5-31orEngine Oil Life
System (DURAMAX
®Diesel) on page 5-33orEngine
Oil Life System (Caterpillar®Diesel Engine) on
page 5-34.
Engine Overspeed Warning Light
If your vehicle has this
light, it will come on if your
engine is operating at
too many revolutions
per minute (rpm).
It will also come on for a moment as a check when you
start your engine.
If it comes on when you’re driving, reduce your engine
speed immediately.
Engine Shutdown Warning Light
If your vehicle has the
engine shutdown feature,
this light will come on
when engine shutdown is
active.
For more information, seeEngine Alarm and Automatic
ShutdownunderStarting the Diesel Engine on
page 2-15.
3-40

Fuel Gage
Your fuel gage is located
on the right side of your
instrument panel cluster.
When the ignition is on, your fuel gage lets you know
about how much fuel you have left. When the gage first
shows empty, you’ll still have a little fuel left, but you
should get more fuel soon.
If your vehicle has dual fuel tanks, the reading on the
gage is the total fuel left in both tanks.Here are four concerns of some operators. None of
these shows a problem with your fuel gage:•The gage moves a little when you turn a corner or
speed up.
•The gage does not go back to empty when you turn
off the ignition.
•At the gas station, the pump shuts off before the
gage reads full.
•It takes a little more or less fuel to fill up than the
gage indicated.
If you have a Caterpillar
®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
3-45

Water in Fuel Warning Light
If your vehicle has the 6.6L
or 7.8L DURAMAX®diesel
engine, this light will
come on to warn you that
there is water in the
fuel system.
For more information on how this light works, seeWater
in Fuel on page 5-10.
Air Filter Restriction Indicator
If your vehicle has this
feature, the gage is
located above the
switchbank in the center of
the instrument panel. It
monitors the engine
air filter.
As the filter gets dirty, the yellow indicator will begin to
rise. When it reaches 25 inches of vacuum on the
scale, the filter should be replaced.
After replacing the filter, reset the gage by pressing in
the yellow reset button at the bottom of the gage.
If you have a Caterpillar
®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
3-46

Other Service Items........................................5-70
Fuel Filter....................................................5-70
Primary Fuel Filter and Water Separator..........5-71
Secondary Fuel Filter and Water
Separator/Heater (Caterpillar
®Diesel)...........5-71
Automatic Ether Injection System
(Caterpillar
®Diesel)....................................5-72
Front Wheel Bearings with Oil-Filled Hubs........5-73
Air Conditioning System.................................5-74
Tires..............................................................5-74
Inflation - Tire Pressure.................................5-75
Wheel Loading.............................................5-75
Dual Tire Operation.......................................5-76
When It Is Time for New Tires.......................5-76
Wheel Alignment and Tire Balance..................5-77
Tightening the Wheel Nuts.............................5-77
Wheel Replacement......................................5-81
If a Tire Goes Flat........................................5-82
Appearance Care............................................5-83
Cleaning the Inside of Your Vehicle.................5-83
Fabric/Carpet...............................................5-85
Instrument Panel, Vinyl, and Other Plastic
Surfaces..................................................5-86
Care of Safety Belts......................................5-86
Weatherstrips...............................................5-86
Washing Your Vehicle...................................5-87Cleaning Exterior Lamps/Lenses.....................5-87
Finish Care..................................................5-87
Windshield and Wiper Blades.........................5-88
Aluminum or Chrome-Plated Wheels................5-89
Tires...........................................................5-89
Sheet Metal Damage.....................................5-89
Finish Damage.............................................5-89
Underbody Maintenance................................5-90
Chemical Paint Spotting.................................5-90
Vehicle Identi cation......................................5-91
Vehicle Identification Number (VIN).................5-91
Service Statement.........................................5-92
Service Parts Identification Label.....................5-92
Electrical System............................................5-92
Add-On Electrical Equipment..........................5-92
Headlamp Wiring..........................................5-93
Windshield Wiper Fuses................................5-93
Fusible Links................................................5-93
Power Windows and Other Power Options.......5-93
Fuses and Circuit Breakers............................5-93
Instrument Panel Fuse Block..........................5-94
Underhood Fuse Block..................................5-96
Capacities and Speci cations..........................5-99
Normal Maintenance Replacement Parts.........5-104
Section 5 Service and Appearance Care
5-2

Doing Your Own Service Work
{CAUTION:
You can be injured and your vehicle could be
damaged if you try to do service work on a
vehicle without knowing enough about it.
Be sure you have sufficient knowledge,
experience, the proper replacement parts,
and tools before you attempt any vehicle
maintenance task.
Be sure to use the proper nuts, bolts, and
other fasteners. English and metric
fasteners can be easily confused. If you
use the wrong fasteners, parts can later
break or fall off. You could be hurt.If you want to do some of your own service work, you
will want to use the proper service manual. It tells
you much more about how to service your vehicle than
this manual can. To order the proper service manual,
seeService Publications Ordering Information on
page 7-11.
Your vehicle has an airbag system. Before attempting to
do your own service work, seeServicing Your
Airbag-Equipped Vehicle on page 1-61.
You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. SeePart D: Maintenance Record on page 6-35.
5-4

Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage would not be covered under
your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors
recommends against the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs
and the performance of the emission control system may
be affected. The malfunction indicator lamp may turn
on. If this occurs, return to your authorized GM dealer for
service.Diesel Engine Fuel
For the Caterpillar®diesel, see the Caterpillar®
Operation & Maintenance Manual for information
concerning fuel usage.
Notice:Diesel fuel or fuel additives not
recommended in this manual could damage your
fuel system and engine. Your warranty would
not cover this damage. And:
Diesel fuel that has been mixed with engine oil
or automatic transmission uid could damage
your engine and emission controls.
Aftermarket diesel fuel additives are not tested
by General Motors. Some additives, particularly
those which contain alcohol or water
emulsi ers, may damage your fuel system. If
you believe that unique circumstances call for a
fuel additive to be used, consult your dealer
for advice.
If you ever run out of diesel fuel, it can be
difficult to restart your engine. To avoid
this, never let your tank get empty.
If gasoline is ever accidentally added to the fuel
tank, to avoid severe engine damage, do not run the
engine until the fuel tank can be drained.
If you run out of fuel,Running Out of Fuel on page 5-17
tells you how to restart your engine.
5-7

Fuel Priming
If your vehicle has a Caterpillar®diesel engine, see the
Caterpillar®Diesel Engine Operation and Maintenance
Manual provided with your vehicle.
If your vehicle has a DURAMAX
®diesel engine, in
order for the fuel system to work properly, the fuel lines
must be full of fuel and contain no air. If air gets into
the fuel lines, it will be necessary to prime the fuel lines
to eliminate air before operating the vehicle.
Air can get into the fuel lines if any of the following
happen:
•The vehicle runs out of fuel.
•The fuel filter is removed for servicing or
replacement.
•The fuel lines are removed or disconnected for
servicing.
•The fuel filter water drain valve is opened while the
engine is running.If one or more of the above occurred, it is very likely
that air has entered your fuel system and that you will
need to prime the fuel system before operating the
vehicle.
Air in the fuel lines will not harm the engine or the
vehicle. However, the engine may not be able to start
until the fuel system is primed and the air is removed.
5-13