2003 GMC SIERRA service

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-2
Rear Seats
............................................... 1-6
Safety Belts
.............................................. 1-7
Child Restraints
.......................................1-29
Air Bag Systems
......................................1-55
Restraint System Check
............................1-71
Features and Controls..................................... 2-1
Keys
........................................................ 2-2
Doors and Locks
....................................... 2-6
Windows
.................................................2-11
Theft-Deterrent Systems
............................2-13
Starting and Operating Your Vehicle
...........2-15
Mirrors
....................................................2-28
OnStar
®System
......................................2-33
HomeLink®Transmitter
.............................2-35
Storage Areas
.........................................2-39
Vehicle Personalization
.............................2-41
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-2
Climate Controls
......................................3-18
Warning Lights, Gages and Indicators
.........3-24
Driver Information Center (DIC)
..................3-42
Audio System(s)
.......................................3-56Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-46
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-4
Checking Things Under
the Hood
.............................................5-10
All-Wheel Drive
........................................5-45
Rear Axle
...............................................5-46
Front Axle
...............................................5-47
Bulb Replacement
....................................5-48
Windshield Wiper Blade Replacement
.........5-56
Tires
......................................................5-56
Appearance Care
.....................................5-82
Vehicle Identication
.................................5-90
Electrical System
......................................5-91
Capacities and Specications
.....................5-99
Normal Maintenance Replacement Parts
....5-100
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 Sierra Denali Owner ManualM
2003 - Sierra Denali Owner Manual

Never put a rear facing child restraint in the right front
passenger seat unless the air bag is off. Here’s why:
{CAUTION:
A child in a rear-facing child restraint can be
seriously injured or killed if the right front
passenger’s air bag inflates. This is because
the back of the rear-facing child restraint
would be very close to the inflating air bag. Be
sure to turn off the air bag before using a
rear-facing child restraint in the right front seat
position. If a forward-facing child restraint is
suitable for your child, always move the
passenger seat as far back as it will go.
Although a rear seat is a safer place, you can secure a
forward-facing child restraint in the right front seat.
{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 inflate
even though the switch is off. If this ever
happens, have the vehicle serviced promptly.
Until you have the vehicle serviced, don’t let
anyone whom the national government has
identified 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).
See″Air Bag Off Switch″in the Index.
In addition to the AIR BAG OFF switch, your vehicle
may have the passenger sensing system. See
Passenger Sensing System on page 1-66and
Passenger Air Bag Status Indicator on page 3-31for
more on this, including important safety information.
The passenger sensing system is designed to turn off
the right front passenger’s frontal air bag when a
rear facing child restraint is in the right front seat.
1-50
2003 - Sierra Denali

{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 inflate
even though the switch is off. If this ever
happens, have the vehicle serviced promptly.
Until you have the vehicle serviced, don’t let
anyone whom the national government has
identified 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).
See″Air Bag Off Switch″in the Index.
2. Put the 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.4. Buckle the belt. Make sure the release button is
positioned so you would be able to unbuckle the
safety belt quickly if you ever had to.
1-52
2003 - Sierra Denali

{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.
In many crashes severe enough to inflate 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 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 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
are bag inflation. 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 qualified technicians work on your air bag
systems. 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.
1-60
2003 - Sierra Denali

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 inate even though the switch is off. If
this ever happens, don’t let anyone whom the
national government has identied 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
1-64
2003 - Sierra Denali

{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
CAUTION: (Continued)
CAUTION: (Continued)
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 “Air Bag Readiness
Light” 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.
{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.
1-69
2003 - Sierra Denali

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
inflate 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, seeService Publications
Ordering Information on page 7-9.
{CAUTION:
For up to 1 minute after the ignition key is
turned off and the battery is disconnected, an
air bag can still inate during improper
service. You can be injured if you are close to
an air bag when it inates. 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 qualied to do so.
The air bag system does not need regular maintenance.
1-70
2003 - Sierra Denali

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:Your vehicle has a number of features that
can help prevent theft. You can have a lot of
trouble getting into your vehicle if you ever lock
your keys inside. You may even have to damage
your vehicle to get in. So be sure you have
spare keys.
If you ever do get locked out of your vehicle, call the
GM Roadside Assistance Center. SeeRoadside
Assistance Program on page 7-5. If your vehicle is
equipped with the OnStar
®system with an active
subscription and you lock your keys inside the vehicle,OnStar
®may be able to send a command to unlock
your vehicle. SeeOnStar®System on page 2-33
for 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 modications to this system by other than
an authorized service facility could void authorization to
use this equipment.
2-3
2003 - Sierra Denali