Page 397 of 458

Fuse Usage
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
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 TrailerFuse Usage
51 Climate Control Blower
52 Ignition B
63Spare (Gas), Engine Control
Module Actuator (Diesel)
64 Spare
Relays 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
397
Page 413 of 458

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.
413
Page 414 of 458

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.
414
Page 443 of 458
OnStar
If your vehicle has OnStar®and you subscribe
to the OnStar®services, please refer to the
OnStar®Terms and Conditions for information
on data collection and use.
Navigation System
If your vehicle has anavigation system,
use of the system may result in the storage of
destinations, addresses, telephone numbers,
and other trip information.Please refer to
the navigation system operating manual for
information on stored data and for deletion
instructions.
Radio Frequency
Identi cation (RFID)
RFIDtechnology is used in some vehicles for
functions such as tire pressure monitoring
and ignition system security, as well as in
connection with conveniences such as key fobs
for remote door locking/unlocking and starting,
and in-vehicle transmitters for garage door
openers. RFID technology in GM vehicles does
not use or record personal information or link
with any other GM system containing personal
information.
443
Page 451 of 458

Headlamps (cont.)
Halogen Bulbs......................................... 340
High/Low Beam Changer......................... 149
On Reminder........................................... 156
Heater......................................................... 160
Highbeam On Light..................................... 185
Highway Hypnosis....................................... 253
Hill and Mountain Roads............................. 254
Hood
Checking Things Under............................ 300
Release................................................... 300
Horn............................................................ 146
How to Use This Manual................................ 4
How to Wear Safety Belts Properly............... 22
I
Ignition Positions......................................... 120
Infants and Young Children, Restraints.......... 44
Inflation - Tire Pressure............................... 354
Instrument Panel
Overview.................................................. 144
Instrument Panel (I/P)
Brightness................................................ 157
Cluster..................................................... 167
J
Jump Starting.............................................. 330
K
Keyless Entry System................................. 104
Keys........................................................... 102
L
Labeling, Tire Sidewall................................. 347
Lamps
Dome....................................................... 157
Dome Lamp Override............................... 157
Reading................................................... 158
LATCH System
Child Restraints......................................... 54
Light
Airbag Off................................................ 170
Airbag Readiness..................................... 169
Anti-Lock Brake System Warning............. 176
Brake System Warning............................. 175
Change Engine Oil................................... 183
Charging System..................................... 174
Check Gages Warning............................. 185
Cruise Control.......................................... 184
451