
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

{CAUTION:
If the air bag readiness light in the instrument
panel cluster ever comes on when you have
turned off the air bag, it means that something
may be wrong with the air bag system. The
right front passenger's air bag could in¯ate
even though the switch is off. If this ever
happens, have the vehicle serviced promptly.
Until you have the vehicle serviced, do not let
anyone whom the national government has
identi®ed as a member of a passenger air bag
risk group sit in the right front passenger's
position (for example, do not secure a
rear-facing child restraint in the right front
passenger's seat). See²Air Bag Off Switch²in
the Index.1. Your vehicle has a right front passenger's frontal air
bag. See
Air Bag Off Switch on page 1-76andPassenger Sensing System on page 1-81. If your
child restraint is forward-facing, move the seat as far
back as it will go before securing the restraint in
this seat. See
Manual Seats on page 1-3orPower
Seats on page 1-4. If you need to use a rear-facing
child restraint in this seat, make sure the air bag
is off once the child restraint has been installed.
When the passenger sensing system or the air bag
off switch has turned off the right front passenger's
frontal air bag, the off indicator in the passenger
air bag status indicator should light and stay lit when
you turn the ignition to RUN or START. See
Passenger Air Bag Status Indicator on page 3-40.
2. Find the LATCH anchorages where the bottom of
the seatback meets the back of the cushion.
3. Put the child restraint on the seat.
4. Attach and tighten the LATCH attachments on the
child restraint to the LATCH anchorages in the
vehicle. The child restraint instructions will show
you how.
5. If the child restraint is forward-facing, attach and
tighten the top tether to the top tether anchorage.
The child restraint instructions will show you
how. Also see
Top Strap on page 1-43.
1-53

A rear seat is a safer place to secure a forward facing
child restraint. SeeWhere to Put the Restraint on
page 1-42. If you need to secure a forward-facing child
restraint in the right front seat position, move the
seat as far back as it will go before securing a
forward-facing child restraint. See
Manual Seats on
page 1-3orPower Seats on page 1-4.
{CAUTION:
If the air bag readiness light in the instrument
panel cluster ever comes on when you have
turned off the air bag, it means that something
may be wrong with the air bag system. The
right front passenger's air bag could in¯ate
even though the switch is off. If this ever
happens, have the vehicle serviced promptly.
Until you have the vehicle serviced, do not let
anyone whom the national government has
identi®ed as a member of a passenger air bag
risk group sit in the right front passenger's
position (for example, do not secure a
rear-facing child restraint in the right front
passenger's seat). See²Air Bag Off Switch²in
the Index.If your child restraint is equipped with the LATCH
system, see
Lower Anchorages and Top Tethers for
Children (LATCH System) on page 1-48. SeeTop Strap
on page 1-43if your child restraint has one.
If your child restraint does not have the LATCH system,
you will be using the lap-shoulder belt to secure the
child restraint in this position. Be sure to follow the
instructions that came with the child restraint. Secure
the child in the child restraint when and as the
instructions say.
1. Your vehicle has a right front passenger's frontal air
bag. See
Air Bag Off Switch on page 1-76andPassenger Sensing System on page 1-81. If your
child restraint is forward-facing, move the seat as far
back as it will go before securing the restraint in
this seat. See
Manual Seats on page 1-3orPower
Seats on page 1-4. If you need to use a rear-facing
child restraint in this seat, make sure the air bag
is off once the child restraint has been installed.
When the passenger sensing system or the air bag
off switch has turned off the right front passenger's
frontal air bag, the off indicator in the passenger
air bag status indicator should light and stay lit when
you turn the ignition to RUN or START. See
Passenger Air Bag Status Indicator on page 3-40.
2. Put the child restraint on the seat.
1-66

{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). You or someone
else could be seriously injured. Be sure to set
the parking brake before placing the transfer
case in NEUTRAL. See
Parking Brake on
page 2-48
.
NEUTRAL:Shift the vehicle's transfer case to
NEUTRAL only when towing your vehicle. See
Recreational Vehicle Towing on page 4-54orTowing
Your Vehicle on page 4-53for more information.Indicator lights in the switches show which setting your
transfer case is in. The indicator lights will come on
brie¯y when you turn on the ignition and one will stay on.
If the lights do not come on, you should take your
vehicle to your dealer for service. An indicator light will
¯ash while the transfer case is being shifted. It will
remain illuminated when the shift is complete. If
for some reason the transfer case cannot make a
requested shift, it will return to the last chosen setting.
If the SERVICE 4WD light stays on, you should take
your vehicle to your dealer for service. See
Service on
page 5-3for further information.
Shifting into 4HI or AUTO 4WD
Press and release the 4HI or AUTO 4WD switch. This
can be done at any speed (except when shifting
from 4LO), and the indicator light will ¯ash while shifting.
It will remain illuminated when the shift is completed.
Shifting into 2HI
Press and release the 2HI switch. This can be done at
any speed (except when shifting from 4LO).
2-41

g(4LO):This setting also engages your front axle to
give you extra traction. You may never need 4LO. It
sends the maximum power to all four wheels. You might
choose 4LO if you were driving off-road in sand, mud
or deep snow and climbing or descending steep hills.
Indicator lights in the switches show you which
setting you are in. The indicator lights will come on
brie¯y when you turn on the ignition and the last chosen
setting will stay on. If the lights do not come on, you
should take your vehicle in for service. An indicator light
will ¯ash while shifting. It will remain illuminated when
the shift is completed. If for some reason the transfer
cannot make a requested shift, it will return to the
last chosen setting.
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). You or someone
else could be seriously injured. Be sure to set
the parking brake before placing the transfer
case in NEUTRAL. See
Parking Brake on
page 2-48
.
NEUTRAL:Shift the vehicle's transfer case to
NEUTRAL only when towing your vehicle. See
Recreational Vehicle Towing on page 4-54orTowing
Your Vehicle on page 4-53for more information.
Shifting from 2HI to 4HI
Press and release the 4HI switch. This can be done at
any speed, and the front axle will lock automatically
with some delay.
Shifting from 4HI to 2HI
Press and release the 2HI switch. This can be done at
any speed, and the front axle will unlock automatically
with some delay.
2-45

Auxiliary Roof Mounted Lamp Switch
If your vehicle has this feature, this switch includes
wiring provisions for a dealer or a quali®ed service
center to install an auxiliary roof lamp.
This switch is located on
the center of the
instrument panel near the
comfort controls.
When the switch wiring is connected to an auxiliary roof
mounted lamp, pressing the switch will activate the lamp
and illuminate an indicator light near the switch. Pressing
the switch again will turn off the roof mounted lamp.
If your vehicle has this switch, your vehicle may have
the snow plow prep package. For further information see
ªSnow Plow Prep Package².
Cargo Lamp
The cargo lamp button is
located on the left side of
the instrument panel.
Press the button to turn the cargo lamp on. Press the
button again to turn it off.
An indicator light on the instrument panel will illuminate
when the cargo lamp is turned on and the ignition
key is turned to RUN.
3-18

If the word OFF or the off symbol is lit on the passenger
air bag status indicator, it means that the passenger
sensing system or the air bag off switch has turned off
the right front passenger's air bag. See
Passenger
Sensing System on page 1-81orAir Bag Off Switch on
page 1-76for more on this, including important safety
information.
{CAUTION:
If the right front passenger's air bag is turned
off for a person who isn't in a risk group
identi®ed by the national government, that
person won't have the extra protection of an
air bag. In a crash, the air bag wouldn't be able
to in¯ate and help protect the person sitting
there. Don't turn off the passenger's air bag
unless the person sitting there is in a risk
group. See²Air Bag Off Switch²in the Index
for more on this, including important safety
information.If, after several seconds, all status indicator lights
remain on, or if there are no lights at all, there may be a
problem with the lights or the passenger sensing
system. See your dealer for service.
{CAUTION:
If the air bag off indicator and the air bag
readiness light ever come on together, it
means that something may be wrong with the
air bag system. If this ever happens, have the
vehicle serviced promptly, because an
adult-size person sitting in the right front
passenger seat may not have the protection of
the air bag. See²Air Bag Readiness Light²in
the Index.
3-41

You can only drive for a short time with the reading in
either warning zone. If you must drive, turn off all
unnecessary accessories.
Readings in either warning zone indicate a possible
problem in the electrical system. Have the vehicle
serviced as soon as possible.
Up-Shift Light
This light is used on some
models with manual
transmissions.
The shift indicator light will show you when to shift to
the next highest gear, and will help you get the best fuel
economy.
Brake System Warning Light
With the ignition on, the brake system warning light will
¯ash when you set the parking brake. The light will
¯ash if the parking brake doesn't release fully. If you try
to drive with the parking brake engaged, a chime will
sound when the vehicle speed is greater than
3 mph (5 km/h).
Your vehicle's hydraulic brake system is divided into two
parts. If one part isn't working, the other part can still
work and stop you. For good braking, though, you need
both parts working well.
If the warning light comes on and a chime sounds there
could be a brake problem. Have your brake system
inspected right away.
3-43