Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-3
Rear Seats
..............................................1-12
Safety Belts
.............................................1-14
Child Restraints
.......................................1-35
Airbag System
.........................................1-68
Restraint System Check
............................1-87
Features and Controls..................................... 2-1
Keys
........................................................ 2-3
Doors and Locks
......................................2-10
Windows
.................................................2-15
Theft-Deterrent Systems
............................2-18
Starting and Operating Your Vehicle
...........2-22
Mirrors
....................................................2-55
Object Detection Systems
..........................2-63
OnStar
®System
......................................2-65
Universal Home Remote System
................2-68
Storage Areas
.........................................2-74
Sunroof
..................................................2-79
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-4
Climate Controls
......................................3-25
Warning Lights, Gages, and Indicators
........3-34
Driver Information Center (DIC)
..................3-54
Audio System(s)
.......................................3-80Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-50
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-4
Fuel
......................................................... 5-6
Checking Things Under the Hood
...............5-12
Rear Axle
...............................................5-51
Four-Wheel Drive
.....................................5-52
Front Axle
...............................................5-54
Noise Control System
...............................5-56
Headlamp Aiming
.....................................5-56
Bulb Replacement
....................................5-59
Windshield Wiper Blade Replacement
.........5-65
Tires
......................................................5-66
Appearance Care
...................................5-112
Vehicle Identi cation
...............................5-121
Electrical System
....................................5-122
Capacities and Speci cations
...................5-130
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance Information.................... 7-1
Customer Assistance and Information
........... 7-2
Reporting Safety Defects
...........................7-14
Vehicle Data Recording and Privacy
...........7-16
Index................................................................ 1
2008 GMC Sierra Owner ManualM
Front Seats......................................................1-3
Manual Seats................................................1-3
Power Seats..................................................1-4
Manual Lumbar..............................................1-5
Power Lumbar...............................................1-5
Heated Seats.................................................1-6
Memory Seat, Mirrors, and Pedals....................1-6
Reclining Seatbacks........................................1-8
Head Restraints............................................1-10
Seatback Latches.........................................1-11
Center Seat.................................................1-12
Rear Seats.....................................................1-12
Rear Seat Operation (Full Bench)...................1-12
Rear Seat Operation (Split Bench)..................1-13
Safety Belts...................................................1-14
Safety Belts: They Are for Everyone................1-14
How to Wear Safety Belts Properly.................1-19
Lap-Shoulder Belt.........................................1-28
Safety Belt Use During Pregnancy..................1-33
Lap Belt (Crew and Extended Cab).................1-34
Safety Belt Extender.....................................1-35Child Restraints.............................................1-35
Older Children..............................................1-35
Infants and Young Children............................1-38
Child Restraint Systems.................................1-42
Where to Put the Restraint.............................1-44
Lower Anchors and Tethers for Children
(LATCH)..................................................1-45
Securing a Child Restraint in a Rear Seat
Position...................................................1-55
Securing a Child Restraint in the Center Front
Seat Position............................................1-57
Securing a Child Restraint in the Right Front
Seat Position (With Airbag Off Switch)..........1-58
Securing a Child Restraint in the Right Front
Seat Position (With Passenger Sensing
System)...................................................1-62
Securing a Child Restraint in the Right
Front Seat Position (Heavy Duty Crew
Cab Only)...............................................
.1-66
Section 1 Seats and Restraint Systems
1-1
Lap-Shoulder Belt
All seating positions in your vehicle have a lap-shoulder
belt except for the center front passenger position (if
equipped) if your vehicle is a crew or extended
cab, which has a lap belt. SeeLap Belt (Crew and
Extended Cab) on page 1-34for more information.
Here is how to wear a lap-shoulder belt properly.
1. Adjust the seat, if the seat is adjustable, so you can
sit up straight. To see how, see “Seats” in the Index.
2. Pick up the latch plate and pull the belt across you.
Do not let it get twisted.
The lap-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.
If you ever pull the shoulder portion of a passenger
belt out all the way, you may engage the child
restraint locking feature. If this happens, just let the
belt go back all the way and start again.
Engaging the child restraint locking feature may
affect the passenger sensing system. See
Passenger Sensing System on page 1-80.3. 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 1-35.
Make sure the release button on the buckle is
positioned so you would be able to unbuckle the
safety belt quickly if necessary.
4. If equipped with a shoulder belt height adjuster,
move it to the height that is right for you. Improper
shoulder belt height adjustment could reduce
the effectiveness of the safety belt in a crash. See
“Shoulder Belt Height Adjustment” later in this
section.
1-28
Safety Belt Pretensioners
Your vehicle has safety belt pretensioners for front
outboard occupants. Although you cannot see them,
they are part of the safety belt assembly. They can help
tighten the safety belts during the early stages of a
moderate to severe frontal, near frontal, or rear crash if
the threshold conditions for pretensioner activation
are met. And, if your vehicle has side impact airbags,
safety belt pretensioners can help tighten the safety
belts in a side crash or a rollover event.
Pretensioners work only once. If they activate in a
crash, you will need to get new ones, and probably other
new parts for your safety belt system. SeeReplacing
Restraint System Parts After a Crash on page 1-88.
Rear Safety Belt Comfort Guides
Rear shoulder belt comfort guides may provide added
safety belt comfort for older children who have outgrown
booster seats and for some adults. When installed on
a shoulder belt, the comfort guide positions the belt
away from the neck and head.There is one guide for each outboard passenger
position in the rear seat. Here is how to install a comfort
guide to the shoulder belt:
1. Remove the guide from its storage clip on the
interior body.
2. Place the guide over the belt and insert the two
edges of the belt into the slots of the guide.
1-31
Safety Belt Extender
If the vehicle’s safety belt will fasten around you, you
should use it.
But if a safety belt is not long enough, your dealer/
retailer will order you an extender. When you go in to
order it, take the heaviest coat you will wear, so
the extender will be long enough for you. To help avoid
personal injury, do not let someone else use it, and
use it only for the seat it is made to t. The extender has
been designed for adults. Never use it for securing
child seats. To wear it, attach it to the regular safety belt.
For more information, see the instruction sheet that
comes with the extender.
Child Restraints
Older Children
Older children who have outgrown booster seats should
wear the vehicle’s safety belts.
1-35
The manufacturer’s instructions that come with the
booster seat, state the weight and height limitations for
that booster. Use a booster seat with a lap-shoulder
belt until the child passes the below t test:
Sit all the way back on the seat. Do the knees bend
at the seat edge? If yes, continue. If no, return to
the booster seat.
Buckle the lap-shoulder belt. Does the shoulder belt
rest on the shoulder? If yes, continue. If no, try
using the rear safety belt comfort guide. See “Rear
Safety Belt Comfort Guides” underLap-Shoulder
Belt on page 1-28for more information. If the
shoulder belt still does not rest on the shoulder,
then return to the booster seat.
Does the lap belt t low and snug on the hips,
touching the thighs? If yes, continue. If no, return to
the booster seat.
Can proper safety belt t be maintained for the
length of the trip? If yes, continue. If no, return
to the booster seat.
Q:What is the proper way to wear safety belts?
A:An older child should wear a lap-shoulder belt and
get the additional restraint a shoulder belt can
provide. The shoulder belt should not cross the face
or neck. The lap belt should t snugly below the
hips, just touching the top of the thighs. This applies
belt force to the child’s pelvic bones in a crash. It
should never be worn over the abdomen, which
could cause severe or even fatal internal injuries in
a crash.
Also see “Rear Safety Belt Comfort Guides” under
Lap-Shoulder Belt on page 1-28.
According to accident statistics, children and infants are
safer when properly restrained in the rear seating
positions than in the front seating positions.
In a crash, children who are not buckled up can strike
other people who are buckled up, or can be thrown
out of the vehicle. Older children need to use safety
belts properly.
1-36
{CAUTION:
Never do this.
Here a child is sitting in a seat that has a
lap-shoulder belt, but the shoulder part is
behind the child. In a crash, the child would
not be restrained by the shoulder belt. The
child might slide under the lap belt. The belt
force would then be applied right on the
abdomen. That could cause serious or fatal
injuries. The child could also move too far
forward increasing the chance of head and
neck injury. The shoulder belt should go over
the shoulder and across the chest.
Infants and Young Children
Everyone in a vehicle needs protection! This includes
infants and all other children. Neither the distance
traveled nor the age and size of the traveler changes
the need, for everyone, to use safety restraints. In fact,
the law in every state in the United States and in
every Canadian province says children up to some age
must be restrained while in a vehicle.
1-38
{CAUTION:
Children can be seriously injured or strangled if
a shoulder belt is wrapped around their neck
and the safety belt continues to tighten. Never
leave children unattended in a vehicle and never
allow children to play with the safety belts.
Every time infants and young children ride in vehicles,
they should have the protection provided by appropriate
restraints. Children who are not restrained properly can
strike other people, or can be thrown out of the vehicle. In
addition, young children should not use the vehicle’s
adult safety belts alone; they need to use a child restraint.
{CAUTION:
People should never hold an infant in their
arms while riding in a vehicle. An infant does
not weigh much — until a crash. During a
crash an infant will become so heavy it is not
CAUTION: (Continued)
CAUTION: (Continued)
possible to hold it. For example, in a crash at
only 25 mph (40 km/h), a 12 lb (5.5 kg) infant
will suddenly become a 240 lb (110 kg) force
on a person’s arms. An infant should be
secured in an appropriate restraint.
1-39