GMC YUKON DENALI 2002 Workshop Manual

1-44 How the Air Bag Systems Work
Where are the air bags?
The driver's frontal air bag is in the middle of the
steering wheel.
The right front passenger's frontal air bag is in the
instrument panel on the passenger's side.
The driver's side impact air bag is in the side of the
driver's seatback closest to the door.

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The right front passenger's side impact air bag is in the
side of the passenger's seatback closest to the door.
CAUTION:
If something is between an occupant and an air
bag, the bag might not inflate properly or it
might force the object into that person causing
severe injury or even death. The path of an
inflating air bag must be kept clear. Don't put
anything between an occupant and an air bag,
and don't attach or put anything on the steering
wheel hub or on or near any other air bag
covering. Don't let seat covers block the inflation
path of a side impact air bag.

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When should an air bag inflate?
The driver's and right front passenger's frontal air bags
are designed to inflate in moderate to severe frontal or
near
-frontal crashes. But they are designed to inflate
only if the impact speed is above the system's designed
ªthreshold level.º
If your vehicle goes straight into a wall that doesn't move
or deform, the threshold level is about 9 to 16 mph
(14 to 26 km/h). The threshold level can vary, however,
with specific vehicle design, so that it can be somewhat
above or below this range.
If your vehicle strikes something that will move or
deform, such as a parked car, the threshold level will be
higher. The driver's and right front passenger's frontal
air bags are not designed to inflate in rollovers, rear
impacts, or in many side impacts because inflation
would not help the occupant.
The side impact air bags are designed to inflate in
moderate to severe side crashes. A side impact air bag
will inflate if the crash severity is above the system's
designed ªthreshold level.º The threshold level can vary
with specific vehicle design. Side impact air bags are not
designed to inflate in frontal or near
-frontal impacts,
rollovers or rear impacts, because inflation would not
help the occupant. A side impact air bag will only
deploy on the side of the vehicle that is struck.In any particular crash, no one can say whether an air
bag should have inflated simply because of the damage
to a vehicle or because of what the repair costs were. For
frontal air bags, inflation is determined by the angle of
the impact and how quickly the vehicle slows down in
frontal and near
-frontal impacts. For side impact air
bags, inflation is determined by the location and severity
of the impact.
The air bag system is designed to work properly under
a wide range of conditions, including off
-road usage.
Observe safe driving speeds, especially on rough terrain.
As always, wear your safety belt. See ªOff
-Road
Drivingº in the Index for more tips on off
-road driving.
What makes an air bag inflate?
In an impact of sufficient severity, the air bag sensing
system detects that the vehicle is in a crash. For both
frontal and side impact air bags, the sensing system
triggers a release of gas from the inflator, which inflates
the air bag. The inflator, air bag and related hardware
are all part of the air bag modules inside the steering
wheel, instrument panel and the side of the front
seatbacks closest to the door.

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How does an air bag restrain?
In moderate to severe frontal or near frontal collisions,
even belted occupants can contact the steering wheel or
the instrument panel. In moderate to severe side
collisions, even belted occupants can contact the inside
of the vehicle. The air bag supplements the protection
provided by safety belts. Air bags distribute the force of
the impact more evenly over the occupant's upper body,
stopping the occupant more gradually. But the frontal air
bags would not help you in many types of collisions,
including rollovers, rear impacts, and many side
impacts, primarily because an occupant's motion is not
toward the air bag. Side impact air bags would not help
you in many types of collisions, including frontal or
near frontal collisions, rollovers, and rear impacts,
primarily because an occupant's motion is not toward
those air bags. Air bags should never be regarded as
anything more than a supplement to safety belts, and
then only in moderate to severe frontal or near
-frontal
collisions for the driver's and right front passenger's
frontal air bags, and only in moderate to severe side
collisions for the driver's and right front passenger's
side impact air bags.What will you see after an air bag inflates?
After an air bag inflates, it quickly deflates, so quickly
that some people may not even realize the air bag
inflated. Some components of the air bag module
-- the
steering wheel hub for the driver's air bag, the
instrument panel for the right front passenger's bag, the
side of the seatback closest to the door for the driver and
right front passenger's side impact air bags
-- will be
hot for a short time. The parts of the bag that come into
contact with you may be warm, but not too hot to touch.
There will be some smoke and dust coming from the
vents in the deflated air bags. Air bag inflation doesn't
prevent the driver from seeing or being able to steer the
vehicle, nor does it stop people from leaving the vehicle.

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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.
In many crashes severe enough to inflate an 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 an
air bag inflates, 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 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, when
the system commands air bag inflation and driver's
safety belt usage at deployment. 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, or the air bag
covering on the driver's and right front
passenger's seatback, the bag may not work
properly. You may have to replace the air bag
module in the steering wheel, both the air bag
module and the instrument panel for the right
front passenger's air bag, or both the air bag
module and seatback for the driver's and right
front passenger's side impact air bag. Do not
open or break the air bag coverings.

1-49 Servicing Your Air Bag-Equipped Vehicle
Air bags affect how your vehicle should be serviced.
There are parts of the air bag systems in several places
around your vehicle. Your dealer and the service manual
have information about servicing your vehicle and the
air bag systems. To purchase a service manual, see
ªService and Owner Publicationsº in the Index.
CAUTION:
For up to 10 minutes after the ignition key is
turned off and the battery is disconnected, an air
bag can still inflate during improper service. You
can be injured if you are close to an air bag when
it inflates. Avoid yellow connectors. They are
probably part of the air bag systems. Be sure to
follow proper service procedures, and make sure
the person performing work for you is qualified
to do so.
The air bag systems do not need regular maintenance.
Adding Equipment to Your Air
Bag-Equipped Vehicle
Q:If I add a push bumper or bicycle rack to the
front of my vehicle, will it keep the air bags
from working properly?
A:As long as the push bumper or bicycle rack is
attached to your vehicle so that the vehicle's basic
structure isn't changed, it's not likely to keep the
air bags from working properly in a crash.
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 ªCustomer
Satisfaction Procedureº in the Index.

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Rear Seat Passengers
It's very important for rear seat passengers to buckle up!
Accident statistics show that unbelted people in the rear
seat are hurt more often in crashes than those who are
wearing safety belts.
Rear passengers who aren't safety belted can be thrown
out of the vehicle in a crash. And they can strike others
in the vehicle who are wearing safety belts.
Rear Seat Outside Passenger Positions
Lap-Shoulder Belt
The positions next to the windows have lap
-shoulder
belts. Here's how to wear one properly.
1. Pick up the latch plate and pull the belt across you.
Don't let it get twisted.

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2. Push the latch plate into the buckle until it clicks.
Pull up on the latch plate to make sure it is secure.
When the shoulder belt is pulled out all the way, it
will lock. If it does, let it go back all the way and
start again.
If the belt is not long enough, see ªSafety Belt
Extenderº at the end of this section.
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.
3. To make the lap part tight, pull down on the buckle
end of the belt as you pull up on the shoulder part.

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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'd 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's a sudden stop or a crash.
CAUTION:
You can be seriously hurt if your shoulder belt is
too loose. In a crash, you would move forward
too much, which could increase injury. The
shoulder belt should fit against your body.

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To unlatch the belt, just push the button on the buckle.
Rear Safety Belt Comfort Guides for
Children and Small Adults
Rear shoulder belt comfort guides will provide added
safety belt comfort for older children who have
outgrown booster seats and for small adults. When
installed on a shoulder belt, the comfort guide better
positions the belt away from the neck and head.
There is one guide for each outside passenger position in
the second and third row seats. To provide added safety
belt comfort for children who have outgrown child
restraints and for smaller adults, the comfort guides
may be installed on the shoulder belts.