Page 332 of 410
1
12. Use the wheel wrench
to tighten the wheel
nuts firmly in
a
crisscross sequence as
shown.
c
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.
I
CAUTION: (Continued) Stop somewhere as soon
as you can and have
the nuts tightened with a torque wrench to the
proper torque specification. See “Capacities
and Specifications”
in the Index for wheel nut
torque specification.
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 specification. See “Capacities and
Specifications”
in the index for the wheel nut torque
specification.
5-73
Page 348 of 410
Fuses
10
11 12
13 14
15 16
17
18
19
20
21 22
23
24
25
26
27
28
29
30
31
Usage
Powertrain Control Module B
Fog Lamps
Stop Lamp
Cigarette Lighter
Ignition Coils
Air Suspension Ride
TBD-Ignition
1
Crank
Air Bag
Electric Brake
Cooling Fan
Horn Ignition
E
Electronic Throttle Control
Instrument Panel Cluster, Driver
Information Center
Automatic Shift Lock Control System
Engine 1
Back-up Powertrain Control Module 1
Oxygen Sensor
Air Conditioning
Truck Body Controller
Fuses
32
33
34
35
36
50
51
52
Relays
37
38
39
40
41
42
43
44
45
46 47
Usage
Trailer
Anti-Lock Brakes (ABS) Ignition A
Blower Motor Ignition B Passenger’s Side Trailer Turn
Driver’s Side Trailer Turn
Hazard Flashers
Usage
Blank Rear Window Washer
Fog Lamps
Horn Fuel Pump
Windshield WipersNasher
High-Beam Headlamp
Air Conditioning
Cooling Fan
Headlamp Driver Module
Starter
Miscellaneous Usage
48 Instrument Panel Battery
49 Fuse Puller
5-89
Page 351 of 410
Fuses
35
36
37
38
39
40
41
42
43
44
Usage
Blank Heat Ventilation Air Conditioning B
Front Parking Lamps
Left Turn Signal Heat Ventilation Air Conditioning
1
Truck Body Controller 4
Radio
Trailer Park
Right Turn Signal
Heat Ventilation Air Conditioning
Fuses
45
46
47
48
49
50
51
52
Usage
Rear Fog Lamps
Auxiliary Power
1
Ignition 0
Four-wheel Drive
Blank
Truck Body Controller Ignition Brakes
Truck Body Controller Run
5-92
Page 354 of 410

6 Maintenance Schedule
Maintenance Schedule ...................................... 6-2
Introduction
................................................... 6-2
Maintenance Requirements
.............................. 6-2
How This Section is Organized ......................... 6-3
Part A: Scheduled Maintenance Services
........... 6-4
Using Your Maintenance Schedule
.................... 6-4
Scheduled Maintenance
................................... 6-5
Part
B: Owner Checks and Services ................ 6-10
At Each Fuel Fill
.......................................... 6-10
At Least Once a Month
................................. 6-10
At Least Twice a Year
................................... 6-11
Your
Vehicle and the Environment
.................... 6-2 At
Least Once a Year
................................... 6-12
Part
C: Periodic Maintenance Inspections ......... 6.15
Boot and Seal Inspection
............................ 6.15
Exhaust System Inspection
............................ 6.15
Fuel System Inspection
.................................. 6.15
Engine Cooling System Inspection
................... 6.15
Brake System Inspection
................................ 6-16
Part E: Maintenance Record
........................... 6.19
Steering, Suspension and Front Drive
Axle
Transfer Case and Front Axle
(All-Wheel Drive) Inspection
........................ 6.16
Part D: Recommended Fluids and Lubricants
.... 6-17
6- 1
Page 358 of 410

Scheduled Maintenance
The services shown in this schedule up to 100,000 miles
(166 000 km) should be repeated after 100,000 miles
(166 000 km) at the same intervals for the life of
this vehicle. The services shown at
150,000 miles
(240 000 km) should be repeated at the same interval
after
150,000 miles (240 000 km) for the life of this
vehicle.
See
Part B: Owner Checks and Services on page 6- 10
and Part C: Periodic Maintenance Inspections on
page 6- 15.
Footnotes
t The US. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior
to
the completion of the vehicle 's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the
maintenance be recorded.
+ A good time to check your brakes is during tire
rotation. See Brake System Inspection
on page 6- 16.
Engine Oil Scheduled Maintenance
Change engine oil and filter as indicated by the GM
Oil Life System (or every 12 months, whichever
occurs first). Reset the system.
Your vehicle has a computer system that lets you know
when
to change the engine oil and filter. This is
based on engine revolutions and engine temperature,
and not on mileage. Based on driving conditions,
the mileage
at which an oil change will be indicated can
vary considerably. For the
oil life system to work
properly, you must reset the system every time the oil is
changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE ENGINE
OIL light will come on.
Change your oil as soon as possible within the next
two times you stop for fuel. It is possible that,
if you are
driving under the best conditions, the oil life system
may not indicate that an oil change is necessary for over
a year. However, your engine oil and filter must be
changed at least once a year and at this time the system
must be reset.
It is also important to check your oil
regularly and keep
it at the proper level.
If the system is ever reset accidentally, you must
change your oil at
3,000 miles (5 000 km) since your
last oil change. Remember
to reset the oil life system
whenever the oil is changed. See
Engine Oil on
page 5-13 for information on resetting the system.
After the services are performed, record the date, odometer reading and who performed the service on the
maintenance record pages in Part
E of this schedule.
An Emission Control Service.
6-5
Page 365 of 410

At Least Once a Year
Key Lock Cylinders Service
Lubricate the key lock cylinders with the lubricant
specified in Part
D.
Body Lubrication Service
Lubricate all hood latch assembly, secondary latch,
pivots, spring anchor, release pawl, rear compartment
hinges, outer liftgate handle pivot points, rear door
detent link, roller mechanism, liftgate handle pivot points,
latch bolt, fuel door hinge, cargo door hinge, locks
and folding seat hardware. Part
D tells you what to use.
More frequent lubrication may be required when
exposed to a corrosive environment.
When you are doing this check, the vehicle
could move suddenly.
If it does, you or others
could be injured. Follow the steps below.
1. Before you start, be sure you have enough room
2. Firmly apply both the parking brake and the regular
around
the vehicle.
brake. See
Parking Brake on page 2-25 if
necessary.
Do not use the accelerator pedal, and be ready to
turn
off the engine immediately if it starts.
3. Try to start the engine in each gear. The starter
should work only in PARK
(P) or NEUTRAL (N).
If the starter works in any other position, your
vehicle needs service.
6-1 2
Page 366 of 410
Automatic Transmission Shift Lock
Cmtrol Sy-tem Check
When you are doing this check, the vehicle
could move suddenly.
If it does, you or others
could be injured. Follow the steps below.
1. Before you start, be sure you have enough room
around the vehicle. It should be parked on a level
surface.
2. Firmly apply the parking brake. See Parking Brake
on page
2-25 if necessary.
3. With the engine off, turn the key to the RUN
position, but don’t start the engine. Without applying
the regular brake, try to move the shift lever out
of PARK
(P) with normal effort. If the shift lever
moves out
of PARK (P), your vehicle needs service.
Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn
the ignition key to LOCK in each shift lever position.
The key should turn to LOCK only when the
shift lever is in PARK (P).
The key should come out only
in LOCK.
Be ready to apply the regular brake immediately
if
the vehicle begins to move.
6-1 3
Page 367 of 410

Parking Brake and Automatic
Transmission Park (P) Mechanism
Check
I
When you are doing this check, ur hicle
could begin to move. You or others could be
injured and property could be damaged. Make
sure there is room
in front of your vehicle in
case it begins to roll. Be ready to apply the
regular brake
at once should the vehicle begin
to move.
To check the parking brake’s holding ability: With
the engine running and transmission in NEUTRAL
(N), slowly remove foot pressure from the regular
brake pedal.
Do this until the vehicle is held by the
parking brake only.
To check the PARK (P) mechanism’s holding
ability: With the engine running, shift to PARK
(P).
Then release the parking brake followed by the
regular brake.
Underbody Flushing Service
At least every spring, use plain water to flush any
corrosive materials from the underbody. Take care to
clean thoroughly any areas where mud and other debris
can collect.
Park on a fairly steep hill, with the vehicle facing
downhill. Keeping your foot on the regular brake, set the
parking brake.
6-1 4