Page 1 of 574

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-3
Rear Seats
............................................... 1-9
Safety Belts
.............................................1-11
Child Restraints
.......................................1-33
Airbag System
.........................................1-66
Restraint System Check
............................1-82
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
....................................................2-55
OnStar
®System
......................................2-64
HomeLink®Transmitter
.............................2-66
Storage Areas
.........................................2-70
Sunroof
..................................................2-73
Vehicle Personalization
.............................2-74
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-4
Climate Controls
......................................3-21
Warning Lights, Gages, and Indicators
........3-31
Driver Information Center (DIC)
..................3-50
Audio System(s)
.......................................3-69Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
........ 4-2
Towing
...................................................4-62
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-4
Fuel
......................................................... 5-6
Checking Things Under the Hood
...............5-12
Rear Axle
...............................................5-58
Four-Wheel Drive
.....................................5-58
Front Axle
...............................................5-60
Noise Control System
...............................5-61
Bulb Replacement
....................................5-62
Windshield Wiper Blade Replacement
.........5-72
Tires
......................................................5-72
Appearance Care
...................................5-112
Vehicle Identi cation
...............................5-120
Electrical System
....................................5-121
Capacities and Speci cations
...................5-130
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
2005 GMC Sierra Owner ManualM
Page 9 of 574
Front Seats
Manual Seats
{CAUTION:
You can lose control of the vehicle if you try to
adjust a manual driver’s seat while the vehicle
is moving. The sudden movement could startle
and confuse you, or make you push a pedal
when you do not want to. Adjust the driver’s
seat only when the vehicle is not moving.
If your vehicle has a manual bucket or a split bench
seat, you can adjust it with this lever located at the front
of the seat.
Lift the lever to unlock the seat. Using your body, slide
the seat to where you want it and release the lever.
Try to move the seat with your body to make sure the
seat is locked into place.
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To heat only the seatback, press the vertical button with
the heated seatback symbol. An indicator light on the
seatback button will be lit to designate that only the
seatback is being heated. Additional presses of
the seatback button will cycle through the heat levels for
the seatback only. Press the horizontal button again
to heat the whole seat.
The heated front seats will shut off automatically when
the ignition is turned off.Reclining Seatbacks
To adjust the front seatback, lift the manual lever
located on the outboard side of the seat. Release the
lever to lock the seatback where you want it. Lift
the lever again without pushing on the seatback and the
seatback will go to an upright position.
If your vehicle has power seats with a power recliner,
seePower Seats on page 1-4for further information on
how to operate the reclining seatback feature.
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Page 14 of 574
Head Restraints
Adjust your head restraint so that the top of the restraint
is closest to the top of your head. This position
reduces the chance of a neck injury in a crash.
To raise the head restraint pull up on the head restraint.
Your vehicle may have rear seat head restraints that
can be adjusted up and down.
Seatback Latches
{CAUTION:
If the seatback is not locked, it could move
forward in a sudden stop or crash. That could
cause injury to the person sitting there. Always
press rearward on the seatback to be sure it is
locked.
The seatbacks fold forward to let you access the rear of
the cab.
To fold a front seatback forward, lift the lever at the
base of the seat to release the seatback.
The lever is located on the outboard side of the seat
cushion.
To return the seatback to the upright position, push the
seatback rearward until it latches. After returning the
seatback to its upright position, push and pull on
the seatback to make sure it is locked.
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Page 15 of 574
Rear Seats
Rear Seat Operation (Extended Cab)
Folding the Rear Seat
The extended cab’s rear seat can be folded up to
provide more cargo space. To fold the seat do the
following:
1. Push down on the seat
while pulling forward on
the release strap
located under the rear
seat cushion.2. Pull the seat cushion up until it latches with the
seatback.
3. After latching the seat cushion up, gently pull
forward on it to make sure it is locked.
The extended cab’s rear seat can also be folded open
for more seating space. To use the seat do the following:
1. Push rearward on the seat cushion while pulling
forward on the release strap under the seat
cushion. Pull the seat cushion down until it latches.
2. After latching the seat cushion down, gently pull up
on it to make sure it is locked.
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Page 22 of 574

Q:If I am a good driver, and I never drive far from
home, why should I wear safety belts?
A:You may be an excellent driver, but if you are in an
accident — even one that is not your fault — you
and your passengers can be hurt. Being a good
driver does not protect you from things beyond your
control, such as bad drivers.
Most accidents occur within 25 miles (40 km) of
home. And the greatest number of serious injuries
and deaths occur at speeds of less than
40 mph (65 km/h).
Safety belts are for everyone.
How to Wear Safety Belts Properly
This part is only for people of adult size.
Be aware that there are special things to know about
safety belts and children. And there are different
rules for smaller children and babies. If a child will be
riding in your vehicle, seeOlder Children on page 1-33
orInfants and Young Children on page 1-35. Follow
those rules for everyone’s protection.
First, you will want to know which restraint systems your
vehicle has.
We will start with the driver position.
Driver Position
Lap-Shoulder Belt
The driver has a lap-shoulder belt. Here is how to wear
it properly.
1. Close and lock the door.
2. Adjust the seat so you can sit up straight. To see
how, see “Seats” in the Index.
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Page 23 of 574
3. Pick up the latch plate and pull the belt across you.
Do not let it get twisted.
The shoulder belt may lock if you pull the belt
across you very quickly. If this happens, let the belt
go back slightly to unlock it. Then pull the belt
across you more slowly.
4. Push the latch plate into the buckle until it clicks.
Pull up on the latch plate to make sure it is secure.
If the belt is not long enough, seeSafety Belt
Extender on page 1-32.
Make sure the release button on the buckle is
positioned so you would be able to unbuckle the
safety belt quickly if you ever had to.5. To make the lap part tight, pull down on the buckle
end of the belt as you pull up on the shoulder belt.
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The lap part of the belt should be worn low and snug on
the hips, just touching the thighs. In a crash, this
applies force to the strong pelvic bones. And you would
be less likely to slide under the lap belt. If you slid
under it, the belt would apply force at your abdomen.
This could cause serious or even fatal injuries. The
shoulder belt should go over the shoulder and across
the chest. These parts of the body are best able to take
belt restraining forces.
The safety belt locks if there is a sudden stop or crash,
or if you pull the belt very quickly out of the retractor.
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