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Fuse Usage
15 Door Locks
16 Upfitter Park
17 Not Available
18 Left Rear Park Lamp
19 Pass Turn Mirror
20 Right Rear Park Lamp
21 Trailer Park Lamp
22 Front Park Lamp
32 Auxiliary 1
33 Auxiliary 2Relays Usage
23 Window Retained Accessory Power
24 Auxiliary
25 Rear Window Defogger
26 Courtesy Lamp
27 Cargo Unlock
28 Driver Unlock
29 Park Lamp
30 Door Locks
31 Passenger Unlock
Circuit Breaker Usage
34 Power Window
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Page 390 of 452
Engine Compartment Fuse Block
The fuse block is located in the engine
compartment on the driver’s side of the vehicle.
Fuse Usage
1 Radio Battery
2Powertrain Control Module Battery
(Gas), FOH, Engine Control Module,
Transmission Control Module
Battery (Diesel)
Fuse Usage
3 Left Rear Turn Lamp
4 Right Rear Turn Lamp
5 Back-up Lamps Trailer Wiring
6 Ignition 0
7 Stoplamp
8 Rear Defogger/Heated Mirror
9Right Daytime Running Lamp/
Turn Signal
10Left Daytime Running Lamp/
Turn Signal
11 Truck Body Control Module 4
12 Fuel Pump
13 Trailer
14 Hazard Flashers
15 Horn
16 Truck Body Control Module 3
17 Trailer Stop/Turn Signal
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Fuse Usage
18 Truck Body Control Module 2
19 Truck Body Control Module
20 Remote Function Actuator
21 Engine 2 (Gas), Spare (Diesel)
22 Ignition E
23 Engine 1
24Truck Body Control Module
Ignition 1
25 Spare (Gas), Fuel Heater (Diesel)
26 Inside Rearview Mirror
27 Crankcase
28Brake Transmission Shift
Interlock System
29 Auxiliary Power Outlets
30 Cigarette Lighter
31 Instrument Panel Cluster
32 Air ConditioningFuse Usage
33Spare (Gas), Engine Control
Module (Diesel)
34Canister Vent Solenoid (Gas), Rear
Fog Lamps (Diesel)
35Spare (Gas & LLY Diesel), Fan
Clutch (LMM Diesel)
36Brake Transmission Shift Interlock,
Vehicle Back-Up
37 Airbag
38Powertrain Control Module Ignition 1
(Gas), Engine Control Module,
Transmission Control Module, Glow
Plug Control Module Ignition 1
(Diesel)
39Oxygen Sensor B (Gas),
Spare (Diesel)
40Oxygen Sensor A (Gas),
Spare (Diesel)
41 Windshield Wipers
42 Right Headlamp - Low Beam
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Fuse Usage
43 Left Headlamp - Low Beam
44 Left Headlamp - High Beam
45 Right Headlamp - High Beam
46Truck Body Controller- Accessory
(Gas), Truck Body Controller,
Transmission Control Module
Accessory (Diesel)
47 Front Windshield Wiper
48Anti-lock Brakes, Vehicle Stability
Enhancement System
49 Ignition A
50 Trailer
51 Climate Control Blower
52 Ignition B
63Spare (Gas), Engine Control Module
Actuator (Diesel)
64 SpareRelays Usage
53 Windshield Wiper
54 Air Conditioning
55Spare (Gas), Rear Fog Lamps
(Diesel)
56 Headlamp - High Beam
57 Fuel Pump
58 Headlamp - Low Beam
59 Horn
SPARE (G),
ECM (D)Spare (Gas), Engine Control
Module (Diesel)
STRTR Starter
Circuit Breaker Usage
PWR SEAT Power Seat
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Page 404 of 452

(b)Visually inspect front and rear suspension and
steering system for damaged, loose, or missing
parts, signs of wear, or lack of lubrication. Inspect
power steering lines and hoses for proper
hook-up, binding, leaks, cracks, cha ng, etc.
(c)Visually inspect hoses and have them replaced
if they are cracked, swollen, or deteriorated.
Inspect all pipes, ttings, and clamps; replace with
genuine GM parts as needed. To help ensure
proper operation, a pressure test of the cooling
system and pressure cap and cleaning the outside
of the radiator and air conditioning condenser is
recommended at least once a year.
(d)Visually inspect wiper blades for wear or
cracking. Replace wiper blades that appear worn
or damaged or that streak or miss areas of
the windshield.
(e)Make sure the safety belt reminder light and all
your belts, buckles, latch plates, retractors, and
anchorages are working properly. Look for
any other loose or damaged safety belt system
parts. If you see anything that might keep a safety
belt system from doing its job, have it repaired.
Have any torn or frayed safety belts replaced.Also look for any opened or broken airbag
coverings, and have them repaired or replaced.
The airbag system does not need regular
maintenance.
(f)Lubricate all key lock cylinders, hood hinges,
hood prop rod pivot, hood latch assembly,
secondary latch, pivots, spring anchor, release
pawl, rear compartment hinges, latches, locks, fuel
door hinge, and any moving seat hardware.
More frequent lubrication may be required when
exposed to a corrosive environment. Applying
silicone grease on weatherstrips with a clean cloth
will make them last longer, seal better, and not
stick or squeak.
(g)Vehicles with Gross Vehicle Weight Rating
(GVWR) above 10,000 lbs (4 536 kg) only: Inspect
shields for damage or looseness. Adjust or
replace as required. This is a Noise Emission
Control Service. Applicable to vehicles sold in the
United States and recommended for vehicles
sold in Canada.
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Page 407 of 452

At Least Once a Year
Starter Switch Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before you start, be sure you have enough
room around the vehicle.
2. Firmly apply both the parking brake and the
regular brake. SeeParking Brake on
page 128.
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
vehicle should start only in PARK (P) or
NEUTRAL (N). If the vehicle starts in any
other position, contact your GM Goodwrench
®
dealer for service.
Automatic Transmission Shift Lock
Control System Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
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. SeeParking
Brake on page 128.
Be ready to apply the regular brake
immediately if the vehicle begins to move.
3. With the engine off, turn the ignition to RUN,
but do not 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), contact
your GM Goodwrench
®dealer for service.
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Ignition Transmission Lock Check
While parked, and with the parking brake set, try
to turn the ignition to LOCK in each shift lever
position.
•The ignition should turn to LOCK only when
the shift lever is in PARK (P).
•The ignition key should come out only in LOCK.
Contact your GM Goodwrench
®dealer if service is
required.
Parking Brake and Automatic
Transmission Park (P) Mechanism Check
{CAUTION:
When you are doing this check, your
vehicle 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.Park on a fairly steep hill, with the vehicle facing
downhill. Keeping your foot on the regular
brake, set the parking brake.
•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.
Contact your GM Goodwrench
®dealer if service is
required.
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.
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Page 410 of 452

Usage Fluid/Lubricant
Key Lock
CylindersMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474).
Chassis
LubricationChassis Lubricant
(GM Part No. U.S. 12377985, in
Canada 88901242) or lubricant
meeting requirements of NLGI #2,
Category LB or GC-LB.
Front Wheel
BearingsWheel bearing lubricant meeting
requirements of NLGI #2,
Category GC or GC-LB
(GM Part No. U.S. 1051344,
in Canada 993037).
Front and
Rear AxleSAE 75W-90 Synthetic
Axle Lubricant
(GM Part No. U.S. 12378261,
in Canada 10953455) or
equivalent meeting GM
Specification 9986115.
Transfer CaseManual Transmission Fluid
(GM Part No. U.S. 88861800,
in Canada 88861801).Usage Fluid/Lubricant
One-Piece
Propshaft Slip
Yoke Spline,
Two-Piece
Propshaft
Slip-in-Tube
SplineSpline Lubricant, Special Lubricant
(GM Part No. U.S. 12345879,
in Canada 10953511) or
lubricant meeting requirements
of GM 9985830.
Hood HingesMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241,
in Canada 10953474).
Weatherstrip
ConditioningWeatherstrip Lubricant
(GM Part No. U.S. 3634770,
in Canada 10953518) or
Dielectric Silicone Grease
(GM Part No. U.S. 12345579,
in Canada 992887).
Weatherstrip
SqueaksSynthetic Grease
with Teflon, Superlube
(GM Part No. U.S. 12371287,
in Canada 10953437).
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