Page 1 of 588

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
Page 46 of 588
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 the ®t of the vehicle's safety belt system. Some
booster seats have a shoulder belt positioner, and
some high-back booster seats have a ®ve-point harness.
A booster seat can also help a child to see out the
window.
1-40
Page 81 of 588

How Does an Air Bag Restrain?
In moderate to severe frontal or near-frontal collisions,
even belted occupants can contact the steering wheel or
the instrument panel. Air bags supplement the
protection provided by safety belts. Air bags distribute
the force of the impact more evenly over the occupant's
upper body, stopping the occupant more gradually.
But air bags would not help you in many types of
collisions, including rollovers, rear impacts and many
side impacts, primarily because an occupant's motion is
not toward those air bags. Air bags should never be
regarded as anything more than a supplement to safety
belts, and then only in moderate to severe frontal or
near-frontal collisions.
What Will You See After an Air Bag
In¯ates?
After an air bag in¯ates, it quickly de¯ates, so quickly that
some people may not even realize the air bag in¯ated.
Some components of the air bag module ± the steering
wheel hub for the driver's air bag, or the instrument panel
for the right front passenger's bag ± will be hot for a short
time. The parts of the bag that come into contact with you
may be warm, but not too hot to touch. There will be
some smoke and dust coming from the vents in thede¯ated air bags. Air bag in¯ation does not prevent the
driver from seeing or being able to steer the vehicle, nor
does it stop people from leaving the vehicle.
{CAUTION:
When an air bag in¯ates, 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
in¯ates, 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.
1-75
Page 95 of 588

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
Delayed Locking...........................................2-10
Programmable Automatic Door Locks..............2-10
Rear Door Security Locks
(Crew Cab)..............................................2-12
Lockout Protection........................................2-13
Rear Doors..................................................2-13
Tailgate.......................................................2-14
Windows........................................................2-16
Manual Windows..........................................2-16
Power Windows............................................2-17
Swing-Out Windows......................................2-18
Sun Visors...................................................2-18
Theft-Deterrent Systems..................................2-19
Content Theft-Deterrent.................................2-19
Passlock
ž....................................................2-21Starting and Operating Your Vehicle................2-21
New Vehicle Break-In....................................2-21
Ignition Positions..........................................2-22
Starting Your Engine.....................................2-23
Engine Coolant Heater..................................2-25
Automatic Transmission Operation...................2-26
Manual Transmission Operation......................2-30
Four-Wheel Drive..........................................2-35
Parking Brake..............................................2-48
Shifting Into Park (P).....................................2-49
Shifting Out of Park (P).................................2-51
Parking Your Vehicle.....................................2-52
Parking Over Things That Burn.......................2-52
Engine Exhaust............................................2-53
Running Your Engine While You Are Parked. . . .2-53
Mirrors...........................................................2-54
Manual Rearview Mirror.................................2-54
Automatic Dimming Rearview Mirror with
OnStar
ž, Compass and Temperature
Display....................................................2-55
Section 2 Features and Controls
2-1
Page 97 of 588
Keys
{CAUTION:
Leaving children in a vehicle with the ignition
key is dangerous for many reasons. They
could operate the power windows or other
controls or even make the vehicle move. The
children or others could be badly injured or
even killed. Do not leave the keys in a vehicle
with children.
2-3
Page 110 of 588
Windows
{CAUTION:
Leaving children, helpless adults, or pets in a
vehicle with the windows closed is dangerous.
They can be overcome by the extreme heat
and suffer permanent injuries or even death
from heat stroke. Never leave a child, a
helpless adult, or a pet alone in a vehicle,
especially with the windows closed in warm or
hot weather.
Manual Windows
Turn the hand crank on each door to manually raise or
lower the manual windows.
2-16
Page 111 of 588

Power Windows
If your vehicle is equipped with power windows, the
controls are located on each of the side doors in
the front and rear.
The driver's door has a switch for the passenger
window as well. Your power windows will work when the
ignition has been turned to ACCESSORY or RUN or
when Retained Accessory Power (RAP) is active.
See ªRetained Accessory Powerº under
Ignition
Positions on page 2-22.Pull up the front of the control with the power window
symbol on it to raise the window.
Press the forward edge of the control down to lower the
window.
Express Down Windows
The driver and front passenger windows also have an
express down feature that allows the windows to
be lowered without holding the switch. Press and hold
the front edge of the window switch for one second
to activate the express down mode. The express down
mode can be canceled at any time by pulling up on
the switch. To open the window partway, lightly tap the
switch until the window is at the desired position.
2-17
Page 112 of 588
Lock-Out Switch
If you have power windows on a Crew Cabž, the
driver's door power window switch has a lockout feature.
The lockout switch is located in front of the window
switches. This feature prevents all windows from
operating, except from the driver's position, when the
driver's door button is engaged. To engage the lock-out
feature press the switch, and an indicator light on the
switch will illuminate. To disengage the lock-out feature
press the switch again, and the indicator light will
turn off. When the button is not engaged, the rear power
windows will operate.
Swing-Out Windows
To open a rear swing-out
window, ¯ip the latch open
and swing the glass out.
The latch will catch when the window is fully open and it
will also hold it in the open position.
Sun Visors
To block out glare, you can swing down the visors. You
can also swing them out to help block glare at the
front and side windows.
The passenger's side sun visor may have a vanity
mirror.
2-18