height GMC SIERRA 2008 Owner's Manual

Manual Lumbar
On vehicles with this feature, turn the knob forward or
rearward to increase or decrease lumbar support.
Power Lumbar
If the seats have power lumbar, the controls used to
operate this feature are located on the outboard side of
the seats.
To increase lumbar support, press and hold the
front of the control.
To decrease lumbar support, press and hold the
rear of the control.
To raise the height of the lumbar support, press
and hold the top of the control.
To lower the height of the lumbar support, press
and hold the bottom of the control.
1-5

Power Reclining Seatbacks
If the seats have power reclining seatbacks, the control
used to recline them is located on the outboard side
of the seat behind the power seat control.
To recline the seatback, tilt the top of the control
rearward.
To bring the seatback forward, tilt the top of the
control forward.
Do not have a seatback reclined if your vehicle is
moving.
Head Restraints
Adjust the head restraint so that the top of the restraint
is at the same height as the top of the occupant’s
head. This position reduces the chance of a neck injury
in a crash.
1-10

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

Shoulder Belt Height Adjuster
Your vehicle has a shoulder belt height adjuster for the
driver and right front passenger.
Adjust the height so that the shoulder portion of the belt
is centered on your shoulder. The belt should be
away from your face and neck, but not falling off your
shoulder. Improper shoulder belt height adjustment
could reduce the effectiveness of the safety belt
in a crash.
To move the adjuster
down for the regular and
crew cabs, squeeze
the buttons (A) on the
sides of the height adjuster
and move the height
adjuster to the desired
position.On the extended cabs,
push down on the release
button (A) and move
the height adjuster to the
desired position.
You can move the adjuster up just by pushing up on the
shoulder belt guide.
After you move the adjuster to where you want it, try to
move it down, without squeezing the buttons for the
regular and crew cabs, or without pushing the release
button for extended cabs, to make sure it has locked into
position.
Regular and Crew Cab
Extended Cab
1-30

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:
Children who are up against, or very close to,
any airbag when it inates can be seriously
injured or killed. Airbags plus lap-shoulder
belts offer protection for adults and older
children, but not for young children and
infants. Neither the vehicle’s safety belt system
nor its airbag system is designed for them.
Young children and infants need the protection
that a child restraint system can provide.
Q:What are the different types of add-on child
restraints?
A:Add-on child restraints, which are purchased by the
vehicle’s owner, are available in four basic types.
Selection of a particular restraint should take
into consideration not only the child’s weight, height,
and age but also whether or not the restraint will
be compatible with the motor vehicle in which it will
be used.
For most basic types of child restraints, there are
many different models available. When purchasing a
child restraint, be sure it is designed to be used
in a motor vehicle. If it is, the restraint will have a
label saying that it meets federal motor vehicle
safety standards.
The restraint manufacturer’s instructions that come
with the restraint state the weight and height
limitations for a particular child restraint. In addition,
there are many kinds of restraints available for
children with special needs.
1-40

Adding Equipment to Your
Airbag-Equipped Vehicle
Q:Is there anything I might add to or change
about the vehicle that could keep the airbags
from working properly?
A:Yes. If you add things that change your vehicle’s
frame, bumper system, height, front end or side
sheet metal, they may keep the airbag system from
working properly. Changing or moving any parts
of the front seats, safety belts, the airbag sensing
and diagnostic module, steering wheel, instrument
panel, roof-rail airbag modules, ceiling headliner
or pillar garnish trim, overhead console, front
sensors, rollover sensor module, or airbag wiring
can affect the operation of the airbag system.
In addition, your vehicle may have a passenger
sensing system for the right front passenger’s
position, which includes sensors that are part of the
passenger’s seat. The passenger sensing system
may not operate properly if the original seattrim is replaced with non-GM covers, upholstery or
trim, or with GM covers, upholstery or trim
designed for a different vehicle. Any object, such as
an aftermarket seat heater or a comfort enhancing
pad or device, installed under or on top of the
seat fabric, could also interfere with the operation of
the passenger sensing system. This could either
prevent proper deployment of the passenger
airbag(s) or prevent the passenger sensing system
from properly turning off the passenger airbag(s).
SeePassenger Sensing System on page 1-80.
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.
SeeCustomer Satisfaction Procedure on page 7-2.
If your vehicle has rollover roof-rail airbags, see
Different Size Tires and Wheels on page 5-86
for additional important information.
1-85

Two-Tiered Loading
Depending on the model of your pick-up, you can
create an upper load platform by positioning
two or four 2 inches (5 cm) by 6 inches (15 cm)
wooden planks across the width of the pickup box.
The planks must be inserted in the pickup box
depressions. The length of the planks must allow
for at least a 3/4 inch (2 cm) bearing surface
on each end of the plank.
When using this upper load platform, be sure the
load is securely tied down to prevent it from
shifting. The load’s center of gravity should be
positioned in a zone over the rear axle. The zone
is located in the area between the front of each
wheel well and the rear of each wheel well.
The center of gravity height must not extend above
the top of the pickup box areboard.
Any load that extends beyond the vehicle’s
taillamp area must be properly marked according
to local laws and regulations.
Remember not to exceed the Gross Axle Weight
Rating (GAWR) of the front or rear axle.Add-On Equipment
When you carry removable items, you may need
to put a limit on how many people you carry
inside your vehicle. Be sure to weigh your vehicle
before you buy and install the new equipment.
Notice:Overloading your vehicle may cause
damage. Repairs would not be covered by your
warranty. Do not overload your vehicle.
Remember not to exceed the Gross Axle Weight
Rating (GAWR) of the front or rear axle.
* Equipment Maximum Weight
Ladder Rack and
Cargo750 lbs (340 kg)
Cross Toolbox and
Cargo400 lbs (181 kg)
Side Boxes and Cargo 250 lbs per side
(113 kg per side)
* The combined weight for all rail-mounted
equipment should not exceed 1,000 lbs (454 kg).
4-42

Brake Wear
Your vehicle has front disc brakes and could have rear
drum brakes or rear disc brakes.
Disc brake pads have built-in wear indicators that make
a high-pitched warning sound when the brake pads
are worn and new pads are needed. The sound can
come and go or be heard all the time your vehicle is
moving, except when you are pushing on the brake
pedal rmly.
{CAUTION:
The brake wear warning sound means that
soon the brakes will not work well. That could
lead to an accident. When you hear the brake
wear warning sound, have your vehicle
serviced.
Notice:Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates can cause a brake
squeal when the brakes are rst applied or lightly
applied. This does not mean something is wrong with
the brakes.Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in
the proper sequence to torque specications in
Capacities and Specifications on page 5-130.
If you have rear drum brakes, they do not have wear
indicators, but if you ever hear a rear brake rubbing
noise, have the rear brake linings inspected immediately.
Rear brake drums should be removed and inspected
each time the tires are removed for rotation or changing.
Drum brakes have an inspection hole to inspect lining
wear during scheduled maintenance. When you have
the front brake pads replaced, have the rear brakes
inspected, too.
Brake linings should always be replaced as complete
axle sets.
Brake Pedal Travel
See your dealer/retailer if the brake pedal does not
return to normal height, or if there is a rapid increase in
pedal travel. This could be a sign that brake service
might be required.
Brake Adjustment
Every time you make a brake stop, the brakes adjust
for wear.
5-44

4. At a wall, measure from the ground upward (A) to
the recorded distance from Step 3 and mark it.
5. Draw or tape a horizontal line (B) on the wall the
width of the vehicle at the height of the mark
in Step 4.
Notice:Do not cover a headlamp to improve beam
cut-off when aiming. Covering a headlamp may
cause excessive heat build-up which may cause
damage to the headlamp.
6. Turn on the low-beam headlamps and place a
piece of cardboard or equivalent in front of the
headlamp not being adjusted. This allows only the
beam of light from the headlamp being adjusted
to be seen on the at surface.7. Locate the vertical headlamp aiming screws, which
are under the hood near each headlamp assembly.
The adjustment screw can be turned with a
E8 Torx
®socket.
8. Turn the vertical aiming screw until the headlamp
beam is aimed to the horizontal tape line. Turn it
clockwise or counterclockwise to raise or lower the
angle of the beam.
5-58