
Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-3
Rear Seats
............................................... 1-9
Safety Belts
.............................................1-11
Child Restraints
.......................................1-33
Air Bag Systems
......................................1-70
Restraint System Check
............................1-87
Features and Controls..................................... 2-1
Keys
........................................................ 2-3
Doors and Locks
....................................... 2-8
Windows
.................................................2-16
Theft-Deterrent Systems
............................2-19
Starting and Operating Your Vehicle
...........2-21
Mirrors
....................................................2-54
OnStar
žSystem
......................................2-64
Storage Areas
.........................................2-66
Vehicle Personalization
.............................2-69
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-4
Climate Controls
......................................3-21
Warning Lights, Gages and Indicators
.........3-33
Driver Information Center (DIC)
..................3-55
Audio System(s)
.......................................3-73Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-53
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-4
Checking Things Under the Hood
...............5-10
Rear Axle
...............................................5-59
Four-Wheel Drive
.....................................5-60
Noise Control System
...............................5-62
Bulb Replacement
....................................5-64
Windshield Wiper Blade Replacement
.........5-74
Tires
......................................................5-76
Appearance Care
...................................5-116
Vehicle Identi®cation
...............................5-125
Electrical System
....................................5-125
Capacities and Speci®cations
...................5-134
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance and Information.............. 7-1
Customer Assistance and Information
........... 7-2
Reporting Safety Defects
...........................7-11
Index................................................................ 1
2004 GMC Sierra Owner ManualM

Vehicle Damage Warnings
Also, in this book you will ®nd these notices:
Notice:These mean there is something that could
damage your vehicle.
A notice will tell you about something that can damage
your vehicle. Many times, this damage would not be
covered by your warranty, and it could be costly. But the
notice will tell you what to do to help avoid the
damage.
When you read other manuals, you might see CAUTION
and NOTICE warnings in different colors or in different
words.
You'll also see warning labels on your vehicle. They use
the same words, CAUTION or NOTICE.
Vehicle Symbols
Your vehicle has components and labels that use
symbols instead of text. Symbols, used on your vehicle,
are shown along with the text describing the operation
or information relating to a speci®c component, control,
message, gage or indicator.
If you need help ®guring out a speci®c name of a
component, gage or indicator, reference the following
topics:
·Seats and Restraint Systems in Section 1
·Features and Controls in Section 2
·Instrument Panel Overview in Section 3
·Climate Controls in Section 3
·Warning Lights, Gages and Indicators in Section 3
·Audio System(s) in Section 3
·Engine Compartment Overview in Section 5
iv

Engine Exhaust
{CAUTION:
Engine exhaust can kill. It contains the gas
carbon monoxide (CO), which you can not see
or smell. It can cause unconsciousness and
death.
You might have exhaust coming in if:
·Your exhaust system sounds strange or
different.
·Your vehicle gets rusty underneath.
·Your vehicle was damaged in a collision.
·Your vehicle was damaged when driving
over high points on the road or over road
debris.
·Repairs were not done correctly.
·Your vehicle or exhaust system had been
modi®ed improperly.
If you ever suspect exhaust is coming into
your vehicle:
·Drive it only with all the windows down to
blow out any CO; and
·Have your vehicle ®xed immediately.
Running Your Engine While You
Are Parked
It is better not to park with the engine running. But if
you ever have to, here are some things to know.
{CAUTION:
Idling the engine with the climate control
system off could allow dangerous exhaust into
your vehicle. See the earlier Caution under
Engine Exhaust on page 2-53.
Also, idling in a closed-in place can let deadly
carbon monoxide (CO) into your vehicle even if
the climate control fan is at the highest setting.
One place this can happen is a garage.
Exhaust Ð with CO Ð can come in easily.
NEVER park in a garage with the engine
running.
Another closed-in place can be a blizzard. See
Winter Driving on page 4-47.
2-53

Outside Convex Mirror
Your passenger's side mirror is convex. A convex
mirror's surface is curved so you can see more from the
driver's seat.
{CAUTION:
A convex mirror can make things (like other
vehicles) look farther away than they really are.
If you cut too sharply into the right lane, you
could hit a vehicle on your right. Check your
inside mirror or glance over your shoulder
before changing lanes.
Outside Heated Mirrors
The outside rearview mirrors with this option have a
defrost mode.
To turn on the defrost feature, press the rear window
defogger button. See ªRear Window Defoggerº under
Dual Automatic Climate Control System on page 3-26for
further information.
OnStaržSystem
OnStaržuses global positioning system (GPS) satellite
technology, wireless communications, and state of
the art call centers to provide you with a wide range of
safety, security, information and convenience services.
A complete OnStar
žuser's guide and the terms and
conditions of the OnStaržSubscription Service
Agreement are included in your OnStarž-equipped
vehicle's glove box literature. For more information, visit
www.onstar.com, contact OnStar
žat 1-888-4-ONSTAR
(1-888-466-7827), or press the blue OnStaržbutton to
speak to an OnStaržadvisor 24 hours a day, 7 days
a week.
A completed Subscription Service Agreement is required
prior to delivery of OnStar
žservices and prepaid
calling minutes are also required for OnStaržPersonal
Calling and OnStaržVirtual Advisor use. Terms and
conditions of the Subscription Service Agreement can be
found at www.onstar.com.
2-64

Instrument Panel Overview...............................3-4
Hazard Warning Flashers................................3-6
Other Warning Devices...................................3-6
Horn.............................................................3-7
Tilt Wheel.....................................................3-7
Turn Signal/Multifunction Lever.........................3-7
Exterior Lamps.............................................3-14
Interior Lamps..............................................3-19
Accessory Power Outlets...............................3-20
Ashtrays and Cigarette Lighter........................3-21
Climate Controls............................................3-21
Climate Control System.................................3-21
Dual Climate Control System..........................3-22
Dual Automatic Climate Control System...........3-26
Warning Lights, Gages and Indicators.............3-33
Warning Lights, Gages, and Indicators.............3-33
Instrument Panel Cluster................................3-34
Speedometer and Odometer...........................3-35
Tachometer.................................................3-35
Safety Belt Reminder Light.............................3-36
Air Bag Readiness Light................................3-36Air Bag Off Light..........................................3-37
Passenger Air Bag Status Indicator.................3-40
Battery Warning Light....................................3-42
Voltmeter Gage............................................3-42
Up-Shift Light...............................................3-43
Brake System Warning Light..........................3-43
Anti-Lock Brake System Warning Light.............3-45
Traction Off Light..........................................3-45
Engine Coolant Temperature Gage..................3-46
Transmission Temperature Gage.....................3-47
Malfunction Indicator Lamp.............................3-49
Oil Pressure Gage........................................3-52
Cruise Control Light......................................3-53
Four-Wheel-Drive Light..................................3-53
Tow/Haul Mode Light....................................3-53
Overdrive Disable.........................................3-53
Fuel Gage...................................................3-54
Low Fuel Warning Light.................................3-54
Driver Information Center (DIC).......................3-55
DIC Operation and Displays...........................3-55
DIC Warnings and Messages.........................3-66
Section 3 Instrument Panel
3-1

The main components of your instrument panel are the
following:
A. Dome Lamp Button. See ªDome Lampsº under
Interior Lamps on page 3-19.
B. Exterior Lamp Controls. See
Exterior Lamps on
page 3-14.
C. Air Outlets. See ªClimate Controlsº in Section 3.
D. Automatic Transfer Case/Electronic Transfer
Case/Traction Assist System (TAS). See
Four-Wheel
Drive on page 2-35.
E. Multifunction Lever. See
Turn Signal/Multifunction
Lever on page 3-7.
F. Instrument Panel Cluster. See
Instrument Panel
Cluster on page 3-34.
G. Gearshift Lever (Automatic Transmission). See
Automatic Transmission Operation on page 2-26.
H. Tow/Haul Selector and Overdrive Disable (Allison
Transmission
žOnly) Button (If Equipped). SeeAutomatic Transmission Operation on page 2-26.
I. Audio System. See
Audio System(s) on page 3-73.
J. Comfort Control System. See
Climate Control
System on page 3-21.
K. Instrument Panel Fuse Block.
Fuses and Circuit
Breakers on page 5-126.L. Hood Release. See
Hood Release on page 5-10.
M. Steering Wheel Control Buttons (If Equipped). See
Driver Information Center (DIC) on page 3-55.
N. Center Instrument Panel Utility Block. See
Fuses
and Circuit Breakers on page 5-126.
O. Parking Brake Release. See
Parking Brake on
page 2-48.
P. Tilt Wheel Lever. See
Tilt Wheel on page 3-7.
Q. Lighter and Accessory Power Outlet. See
Accessory
Power Outlets on page 3-20, andAshtrays and
Cigarette Lighter on page 3-21.
R. Storage Area. See ªStorage Areasº in Section 2.
S. Ashtray. See
Ashtrays and Cigarette Lighter
on page 3-21.
T. Manual Selectable Ride Control (If Equipped). See
Manual Selectable Ride on page 4-11.
U. 4WS Switch (If Equipped). See
QUADRASTEERŸ
on page 4-14.
V. Passenger Air Bag Off Switch. See
Air Bag Off
Switch on page 1-76.
W. Glove Box. See
Glove Box on page 2-66.
3-5

Notice:Improper use of the power outlet can cause
damage not covered by your warranty. Do not
hang any type of accessory or accessory bracket
from the plug because the power outlets are
designed for accessory power plugs only.
Ashtrays and Cigarette Lighter
Your vehicle may be equipped with a front ashtray
located near the center of the instrument panel. Pull on
the door to open it.
Notice:If you put papers or other ¯ammable items
in the ashtray, hot cigarettes or other smoking
materials could ignite them and possibly damage
your vehicle. Never put ¯ammable items in the
ashtray.
To remove the front ashtray, pull the ashtray toward you.
To replace the ashtray, place the ashtray on the slides at
the side of its location in the instrument panel. To use the
cigarette lighter, push it in all the way, and let go. When
it's ready, it will pop back out by itself.
Notice:Holding a cigarette lighter in while it is
heating will not allow the lighter to back away from
the heating element when it is hot. Damage from
overheating may occur to the lighter or heating
element, or a fuse could be blown. Do not hold a
cigarette lighter in while it is heating.
Climate Controls
Climate Control System
Fan Knob
The fan knob on the left side of the control panel
adjusts the fan speed. To increase air¯ow, turn the knob
clockwise. To decrease air¯ow, turn it counterclockwise.
To turn the fan off, turn the knob to the off position.
9(Off):If the fan is off, outside air will still enter the
vehicle, and will be directed based on the position of
the mode knob. The temperature can also be adjusted
using the temperature knob.
3-21

Temperature Knob
The middle knob on the control panel lets you select the
temperature of the air ¯owing into the passenger
area. Turn the knob clockwise toward the red area for
warmer air. Turn the knob counterclockwise toward
the blue area for cooler air.
Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery.
H(Vent):This setting directs the air through the
instrument panel outlets.
)(Bi-Level):Air is delivered through the ¯oor outlets
as well as the instrument panel outlets. The ¯ow can
be divided between vent and ¯oor outlets depending
upon where the knob is placed between the settings.
6(Floor):This setting directs most of the air through
the ¯oor outlets, and the rest of the air is divided
between the windshield defroster outlets and the side
window defroster outlets.
W(Defog):Air¯ow is delivered through the ¯oor
outlets, the windshield defroster outlets and the side
window defroster outlets. The air ¯ow can be divided
between ¯oor and defrost depending upon where
the knob is placed between the settings.
1(Defrost):This setting directs most air through the
windshield defroster outlets, side window defroster
outlets and some through the ¯oor outlets.
Dual Climate Control System
With this system you can control the heating, cooling
and ventilation for your vehicle.
9(Fan):Turn the left knob clockwise or
counterclockwise to increase or decrease the fan speed.
Turn the knob to the off position to turn off the fan. If the
knob is in off outside air will still enter the vehicle, and will
be directed based on the position of the mode knob. The
temperature can also be adjusted using the temperature
levers.
3-22