Page 435 of 484
Fuses Usage
23 Blank
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
36Heat Ventilation Air
Conditioning B
37 Front Parking Lamps
38 Left Turn Signal
39Heat Ventilation Air
Conditioning 1
Fuses Usage
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
BLANK Not Used
BLANK Not Used
BLANK Not Used
BLANK Not Used
BLANK Not Used
BLANK Not Used
5-101
Page 448 of 484

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 2-31.
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 2-31.
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.
6-10
Page 449 of 484

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 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 ush any
corrosive materials from the underbody. Take care to
clean thoroughly any areas where mud and other debris
can collect.
6-11
Page 476 of 484

G
Gage
Check Gages Warning Light..........................3-47
Engine Coolant Temperature.........................3-40
Fuel..........................................................3-48
Oil Pressure...............................................3-44
Speedometer..............................................3-33
Tachometer.................................................3-33
Voltmeter Gage...........................................3-38
Garage Door Opener.......................................2-49
Gasoline
Octane........................................................ 5-5
Speci cations............................................... 5-5
Gate Ajar Light...............................................3-47
Glove Box.....................................................2-53
GM Mobility Reimbursement Program.................. 7-5
H
Hazard Warning Flashers................................... 3-6
Head Restraints............................................... 1-7
Headlamps....................................................3-14
Automatic Headlamp System.........................3-16
Bulb Replacement.......................................5-46
Daytime Running Lamps...............................3-15
Electrical System.........................................5-90
Flash-to-Pass............................................... 3-8
Halogen Bulbs............................................5-46
High/Low Beam Changer................................ 3-8Headlamps (cont.)
On Reminder..............................................3-15
Washer......................................................3-11
Heated Seats................................................... 1-4
Heater...........................................................3-20
Heater...........................................................3-23
Highbeam On Light.........................................3-46
Highway Hypnosis...........................................4-35
Hill and Mountain Roads..................................4-35
HomeLink
®Wireless Control System.................2-49
HomeLink®Wireless Control System Operation....2-50
Hood
Checking Things Under................................5-10
Release.....................................................5-11
Horn............................................................... 3-6
How to Use This Manual...................................... ii
How to Wear Safety Belts Properly...................1-16
I
Ignition Positions.............................................2-19
Infants and Young Children, Restraints...............1-33
In ation -- Tire Pressure..................................5-56
Instrument Panel
Overview..................................................... 3-4
Instrument Panel (I/P)
Brightness..................................................3-17
Cluster.......................................................3-32
6