2004 GMC SIERRA DENALI service

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-3
Rear Seats
............................................... 1-8
Safety Belts
.............................................. 1-8
Child Restraints
.......................................1-29
Air Bag Systems
......................................1-62
Restraint System Check
............................1-79
Features and Controls..................................... 2-1
Keys
........................................................ 2-2
Doors and Locks
....................................... 2-6
Windows
.................................................2-13
Theft-Deterrent Systems
............................2-15
Starting and Operating Your Vehicle
...........2-18
Mirrors
....................................................2-31
OnStar
žSystem
......................................2-36
HomeLinkžTransmitter
.............................2-38
Storage Areas
.........................................2-42
Vehicle Personalization
.............................2-45
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-2
Climate Controls
......................................3-19
Warning Lights, Gages and Indicators
.........3-27
Driver Information Center (DIC)
..................3-46
Audio System(s)
.......................................3-64Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-48
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-4
Checking Things Under the Hood
................. 5-8
All-Wheel Drive
........................................5-46
Rear Axle
...............................................5-47
Front Axle
...............................................5-48
Bulb Replacement
....................................5-49
Windshield Wiper Blade Replacement
.........5-58
Tires
......................................................5-59
Appearance Care
.....................................5-96
Vehicle Identi®cation
...............................5-104
Electrical System
....................................5-105
Capacities and Speci®cations
...................5-114
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance and Information.............. 7-1
Customer Assistance and Information
........... 7-2
Reporting Safety Defects
...........................7-10
Index................................................................ 1
2004 GMC Sierra Denali Owner ManualM

Never put a rear facing child restraint in the right front
passenger's seat unless the air bag is off. Here is why:
{CAUTION:
A child in a rear-facing child restraint can be
seriously injured or killed if the right front
passenger's air bag in¯ates. This is because
the back of the rear-facing child restraint
would be very close to the in¯ating air bag.
Be sure the air bag is off before using a
rear-facing child restraint in the right front seat
position. If you secure a forward-facing child
restraint in the right front seat, always move
the right front passenger seat as far back as it
will go.
A rear seat is a safer place to secure a forward facing
child restraint. See
Where to Put the Restraint on
page 1-39. 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
Power Seats on
page 1-3.
{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). See ªAir Bag Off Switchº in
the Index.
1-48

{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). See ªAir Bag Off Switchº in
the Index.
If your child restraint is equipped with the LATCH
system, see
Lower Anchorages and Top Tethers for
Children (LATCH System) on page 1-44. SeeTop Strap
on page 1-40if 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 1-68andPassenger Sensing System on page 1-73. 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
Power Seats on page 1-3. 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 3-33.
2. Put the child restraint on the seat.
3. Pick up the latch plate, and run the lap and shoulder
portions of the vehicle's safety belt through or
around the restraint. The child restraint instructions
will show you how.
1-58

{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.
In many crashes severe enough to in¯ate the air bag,
windshields are broken by vehicle deformation.
Additional windshield breakage may also occur from the
right front passenger air bag.
·Air bags are designed to in¯ate only once. After
they in¯ate, you will need some new parts for
your air bag system. If you do not get them, the air
bag system will not be there to help protect you
in another crash. A new system will include air bagmodules and possibly other parts. The service
manual for your vehicle covers the need to replace
other parts.
·Your vehicle is equipped with electronic frontal
sensors which help the sensing system distinguish
between a moderate and a more severe frontal
impact. Your vehicle is also equipped with a crash
sensing and diagnostic module, which records
information about the frontal air bag system. The
module records information about the readiness of
the system and when the system commands air
bag in¯ation. It records the status of the driver's
safety belt usage in a crash in which the air
bag deploys or a crash in which the air bag nearly
deploys. The module also records speed, engine
rpm, brake and throttle data.
·Let only quali®ed technicians work on your air bag
systems. Improper service can mean that an air
bag system will not 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.
1-67

To turn off the right front passenger's air bag, insert
your ignition key into the switch, push in, and move the
switch to the off position.
The AIR BAG OFF light will come on to let you know
that the right front passenger's air bag is off. The
right front passenger's air bag will remain off until you
turn it back on again, and the AIR BAG OFF light
will stay on to remind you that the air bag is off.
{CAUTION:
If the air bag readiness light 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, don't 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, don't secure a rear-facing child
restraint in your vehicle) until you have your
vehicle serviced. United States with
Passenger Sensing
System
United States without
Passenger Sensing
System
Canada with Passenger
Sensing SystemCanada without
Passenger Sensing
System
1-71

{CAUTION:
If the air bag readiness light in the instrument
panel cluster ever comes on and stays on, 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's seat may not have the protection
of the frontal air bag. See ªAir Bag Readiness
Lightº in the Index for more on this, including
important safety information.Aftermarket equipment, such as seat covers, can affect
how well the passenger sensing system operates.
You may want to consider not using seat covers or other
aftermarket equipment if your vehicle has the passenger
sensing system. SeeAdding Equipment to Your Air
Bag-Equipped Vehicle on page 1-78for more
information about modi®cations that can affect how the
system operates.
{CAUTION:
Stowing of articles under the passenger's seat
or between the passenger's seat cushion and
seatback may interfere with the proper
operation of the passenger sensing system.
1-77

Servicing Your Air Bag-Equipped
Vehicle
Air bags affect how your vehicle should be serviced.
There are parts of the air bag system in several places
around your vehicle. You don't want the system to
in¯ate while someone is working on your vehicle. Your
dealer and the service manual have information
about servicing your vehicle and the air bag system. To
purchase a service manual, see
Service Publications
Ordering Information on page 7-11.
{CAUTION:
For up to 10 seconds after the ignition key is
turned off and the battery is disconnected, an
air bag can still in¯ate during improper
service. You can be injured if you are close to
an air bag when it in¯ates. Avoid yellow
connectors. They are probably part of the air
bag system. Be sure to follow proper service
procedures, and make sure the person
performing work for you is quali®ed to do so.
The air bag system does not need regular maintenance.
Adding Equipment to Your Air
Bag-Equipped Vehicle
Q:Is there anything I might add to the front or
sides of the vehicle that could keep the air
bags from working properly?
A:Yes. If you add things that change your vehicle's
frame, bumper system, front end or side sheet
metal or height, they may keep the air bag system
from working properly. Also, the air bag system
may not work properly if you relocate any of the air
bag sensors. If you have any questions about
this, you should contact Customer Assistance
before you modify your vehicle. The phone
numbers and addresses for Customer Assistance
are in Step Two of the Customer Satisfaction
Procedure in this manual. See
Customer
Satisfaction Procedure on page 7-2
.
1-78

Your vehicle has one
double-sided key for the
ignition and all door
locks as well as the spare
tire hoist lock, if equipped.
If you ever lose your keys, your dealer will be able to
assist you with obtaining replacements.
Notice:If you ever lock your keys in your vehicle,
you may have to damage the vehicle to get in.
Be sure you have spare keys.
If you ever do get locked out of your vehicle, call the
GM Roadside Assistance Center. See
Roadside
Assistance Program on page 7-6. If your vehicle is
equipped with the OnStaržsystem with an active
subscription and you lock your keys inside the vehicle,
OnStar
žmay be able to send a command to unlock
your vehicle. SeeOnStaržSystem on page 2-36for more information.
Remote Keyless Entry System
Your keyless entry system operates on a radio
frequency subject to Federal Communications
Commission (FCC) Rules and with Industry Canada.
This device complies with Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
1. This device may not cause interference, and
2. This device must accept any interference received,
including interference that may cause undesired
operation of the device.
This device complies with RSS-210 of Industry Canada.
Operation is subject to the following two conditions:
1. This device may not cause interference, and
2. This device must accept any interference received,
including interference that may cause undesired
operation of the device.
Changes or modi®cations to this system by other than
an authorized service facility could void authorization to
use this equipment.
2-3