Page 415 of 470
Relays Usage
37 Blank or Headlamp Washer
38 Rear Window Washer
39 Fog Lamps
40 Horn
41 Fuel Pump
42 Windshield Washer
43 High-Beam Headlamp
44 Air Conditioning
45 Cooling Fan
46 Headlamp Driver ModuleRelays Usage
47 Starter
49 Electric Adjustable Pedal
55 Air Injection Reactor (AIR) Solenoid
57 Powertrain
58Vehicle Stability Enhancement
System (StabiliTrak
®)
Miscellaneous Usage
48 Instrument Panel Battery
5-99
Page 417 of 470
Fuses Usage
6 Driver’s Side Low-Beam Headlamp
7 Rear Window Washer
8 Automatic Transfer Case
9 Windshield Washer
10 Powertrain Control Module B
11 Fog Lamps
12 Stoplamp
13 Cigarette Lighter
14 Ignition Coils
15 Canister Vent
16 Truck Body Controller, Ignition 1
17 Crank
18 Airbag
19 Trailer Electric Brake
20 Cooling Fan
21 Horn
22 Ignition E
23 Electronic Throttle Control
24Instrument Panel Cluster, Driver
Information Center
25 Automatic Shift Lock Control System
26 Engine 1Fuses Usage
27 Back-Up
28 Powertrain Control Module 1
29 Powertrain
30 Air Conditioning
31 Injector Bank A
32 Trailer
33 Anti-lock Brakes (ABS)
34 Ignition A
35 Blower Motor
36 Ignition B
50 Passenger’s Side Trailer Turn
51 Driver’s Side Trailer Turn
52 Hazard Flashers
53 Transmission
54 Oxygen Sensor Bank B
55 Oxygen Sensor Bank A
56 Injector Bank B
57 Headlamp Driver Module
58 Truck Body Controller 1
59 Electric Adjustable Pedal
61Vehicle Stability Enhancement
System (StabiliTrak
®)
5-101
Page 418 of 470
Relays Usage
37 Headlamp Washer
38 Rear Window Washer
39 Fog Lamps
40 Horn
41 Fuel Pump
42 Windshield Wipers/Washer
43 High-Beam Headlamp
44 Air Conditioning
45 Cooling Fan
46 Headlamp Driver Module
47 Starter
49 Electric Adjustable Pedal
60 Powertrain
Miscellaneous Usage
48 Instrument Panel Battery
Rear Underseat Fuse Block
5-102
Page 420 of 470
Fuses Usage
24 Unlock
25 Blank
26 Blank
27OnStar
®Overhead Battery,
OnStar®System
28 Sunroof
29 Rainsense™ Wipers
30 Parking Lamps
31 Truck Body Controller Accessory
32 Truck Body Controller 5
33 Front Wipers
34 Vehicle Stop
35 Transmission Control Module
36 Heat Ventilation Air Conditioning B
37 Front Parking Lamps
38 Left Turn Signal
Fuses Usage
39 Heat Ventilation Air Conditioning I
40 Truck Body Controller 4
41 Radio
42 Trailer Park
43 Right Turn Signal
44 Heat Ventilation Air Conditioning
45 Rear Fog Lamps
46 Auxiliary Power 1
47 Ignition 0
48 Four-Wheel Drive
49 Blank
50 Truck Body Controller Ignition
51 Brakes
52 Truck Body Controller Run
5-104
Page 424 of 470

Maintenance Schedule
Introduction
Important: Keep engine oil at the proper level and
change as recommended.
Have you purchased the GM Protection Plan? The Plan
supplements your new vehicle warranties. See your
Warranty and Owner Assistance booklet or your dealer
for details.
Maintenance Requirements
Notice:Maintenance intervals, checks, inspections,
replacement parts, and recommended uids and
lubricants as prescribed in this manual are necessary
to keep your vehicle in good working condition.
Any damage caused by failure to follow scheduled
maintenance may not be covered by warranty.
Your Vehicle and the Environment
Proper vehicle maintenance not only helps to keep
your vehicle in good working condition, but also helps
the environment. All recommended maintenance is
important. Improper vehicle maintenance can even
affect the quality of the air we breathe. Improper uid
levels or the wrong tire in ation can increase the level
of emissions from your vehicle. To help protect our
environment, and to keep your vehicle in good condition,
be sure to maintain your vehicle properly.
Using the Maintenance Schedule
We at General Motors want to help you keep your
vehicle in good working condition. But we do not know
exactly how you will drive it. You may drive very
short distances only a few times a week. Or you may
drive long distances all the time in very hot, dusty
weather. You may use your vehicle in making deliveries.
Or you may drive it to work, to do errands, or in many
other ways.
Because of all the different ways people use their
vehicles, maintenance needs vary. You may need more
frequent checks and replacements. So please read
the following and note how you drive. If you have any
questions on how to keep your vehicle in good condition,
see your GM Goodwrench
®dealer.
6-2
Page 426 of 470