Page 1 of 424

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-3
Rear Seats
............................................... 1-9
Safety Belts
.............................................1-10
Child Restraints
.......................................1-30
Air Bag System
.......................................1-54
Restraint System Check
............................1-64
Features and Controls..................................... 2-1
Keys
........................................................ 2-3
Doors and Locks
....................................... 2-8
Windows
.................................................2-14
Theft-Deterrent Systems
............................2-17
Starting and Operating Your Vehicle
...........2-20
Mirrors
....................................................2-39
Storage Areas
.........................................2-41
Sunroof
..................................................2-52
Vehicle Personalization
.............................2-54
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-2
Climate Controls
......................................3-17
Warning Lights, Gages and Indicators
.........3-20
Audio System(s)
.......................................3-36
Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-42Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-4
Checking Things Under the Hood
................. 5-8
Rear Axle
...............................................5-47
Four-Wheel Drive
.....................................5-48
Front Axle
...............................................5-49
Bulb Replacement
....................................5-50
Windshield Wiper Blade Replacement
.........5-56
Tires
......................................................5-58
Appearance Care
.....................................5-79
Vehicle Identification
.................................5-87
Electrical System
......................................5-88
Capacities and Specifications
.....................5-94
Normal Maintenance Replacement Parts
......5-96
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance Information.................... 7-1
Customer Assistance Information
.................. 7-2
Reporting Safety Defects
............................ 7-8
Index................................................................ 1
2003 GMC Sonoma Owner ManualM
2003 - Sonoma Owner Manual
Page 32 of 424
To make it shorter, pull the belt, as shown until it is
snug. Buckle and position it the same way as the lap
part of the driver’s safety belt. SeeDriver Position
on page 1-16. Make sure the release button on the
buckle is positioned so you would be able to unbuckle
the safety belt quickly if you ever had to. To unlatch the
belt, just push the button on the buckle.
Don’t use a child restraint on this seat. It won’t work
properly.
Rear Seat Passengers (CrewCab®)
It’s very important for rear seat passengers to buckle up!
Accident statistics show that unbelted people in the
rear seat are hurt more often in crashes than those who
are wearing safety belts.
Rear passengers who aren’t safety belted can be
thrown out of the vehicle in a crash. And they can strike
others in the vehicle who are wearing safety belts.
Rear Seat Outside Passenger Positions
Lap-Shoulder Belt
The positions next to the windows have lap-shoulder
belts. Here’s how to wear one properly.
1-26
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Page 36 of 424
Child Restraints
Older Children
Older children who have outgrown booster seats should
wear the vehicle’s safety belts.If you have a choice, a child should sit next to a window
so that the child can wear a lap-shoulder belt and get
the additional restraint a shoulder belt can provide.
Q:What is the proper way to wear safety belts?
A:If possible, an older child should wear a
lap-shoulder belt and get the additional restraint a
shoulder belt can provide. The shoulder belt
should not cross the face or neck. The lap belt
shouldfit snugly below the hips, just touching the
top of the thighs. It should never be worn over
the abdomen, which could cause severe or even
fatal internal injuries in a crash.
In a crash, children who are not buckled up can strike
other people who are buckled up, or can be thrown
out of the vehicle. Older children need to use safety
belts properly.
1-30
2003 - Sonoma OM
Page 43 of 424
A forward-facing child seat (C-E) provides restraint for
the child’s body with the harness and also sometimes
with surfaces such as T-shaped or shelf-like shields.A booster seat (F-G) is a child restraint designed to
improve thefit of the vehicle’s safety belt system.
Some booster seats have a shoulder belt positioner,
and some high-back booster seats have afive-point
harness. A booster seat can also help a child to see
out the window.
1-37
2003 - Sonoma OM
Page 65 of 424

{CAUTION:
When an air bag inflates, there is dust in the
air. This dust could cause breathing problems
for people with a history of asthma or other
breathing trouble. To avoid this, everyone in
the vehicle should get out as soon as it is safe
to do so. If you have breathing problems but
can’t get out of the vehicle after an air bag
inflates, then get fresh air by opening a
window or a door. If you experience breathing
problems following an air bag deployment,
you should seek medical attention.
•Air bags are designed to inflate only once. After
they inflate, you’ll need some new parts for your
air bag system. If you don’t get them, the air
bag system won’t be there to help protect you in
another crash. A new system will include air
bag modules and possibly other parts. The service
manual for your vehicle covers the need to
replace other parts.
•Your vehicle is equipped with a diagnostic module,
which records information about the air bag
system. The module records information about the
readiness of the system, when the system
commands air bag inflation and driver’s safety belt
usage at deployment.
•Let only qualified technicians work on your air bag
system. Improper service can mean that an air
bag system won’t work properly. See your dealer
for service.
Notice:If you damage the covering for the driver’s
or the right front passenger’s air bag, the bag
may not work properly. You may have to replace the
air bag module in the steering wheel or both the
air bag module and the instrument panel for
the right front passenger’s air bag. Do not open or
break the air bag coverings.
1-59
2003 - Sonoma OM
Page 73 of 424

Keys...............................................................2-3
Remote Keyless Entry System.........................2-4
Remote Keyless Entry System Operation...........2-5
Doors and Locks.............................................2-8
Door Locks....................................................2-8
Power Door Locks..........................................2-9
Programmable Automatic Door Locks................2-9
Rear Door Security Locks..............................2-11
Lockout Protection........................................2-11
Leaving Your Vehicle....................................2-11
Third Door...................................................2-12
Tailgate.......................................................2-12
Windows........................................................2-14
Manual Windows..........................................2-15
Power Windows............................................2-15
Swing-Out Windows......................................2-16
Sliding Rear Window.....................................2-16
Sun Visors...................................................2-16
Theft-Deterrent Systems..................................2-17
Content Theft-Deterrent.................................2-17
Passlock
®....................................................2-19Starting and Operating Your Vehicle................2-20
New Vehicle Break-In....................................2-20
Ignition Positions..........................................2-20
Starting Your Engine.....................................2-22
Engine Coolant Heater..................................2-24
Automatic Transmission Operation...................2-25
Manual Transmission Operation......................2-28
Four-Wheel Drive..........................................2-29
Parking Brake..............................................2-32
Shifting Into Park (P).....................................2-33
Shifting Out of Park (P).................................2-35
Parking Your Vehicle.....................................2-36
Parking Over Things That Burn.......................2-36
Engine Exhaust............................................2-37
Running Your Engine While You Are Parked. . . .2-38
Mirrors...........................................................2-39
Manual Rearview Mirror.................................2-39
Automatic Dimming Rearview Mirror................2-39
Outside Manual Mirror...................................2-39
Outside Power Mirrors...................................2-40
Outside Convex Mirror...................................2-40
Outside Heated Mirrors..................................2-41
Section 2Features and Controls
2-1
2003 - Sonoma OM
Page 75 of 424
Keys
{CAUTION:
Leaving children in a vehicle with the ignition
key is dangerous for many reasons. A child or
others could be badly injured or even killed.
They could operate the power windows or
other controls or even make the vehicle move.
Don’t leave the keys in a vehicle with children.
2-3
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Page 86 of 424
Windows
{CAUTION:
Leaving children in a vehicle with the windows
closed is dangerous. A child can be overcome
by the extreme heat and can suffer permanent
injuries or even death from heat stroke. Never
leave a child alone in a vehicle, especially with
the windows closed in warm or hot weather.
2-14
2003 - Sonoma OM