2011 Chevrolet Municipal Vehicles Technical Manual
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aIr bags faq
can specialty vehicle equipment (e.g. radar devices, video
cameras, computers, meters, radio trees, shotguns, etc.) still be
mounted in cars with passenger side air bags?
Yes, but care must be taken to mount the equipment outside of the deployment zone.
Air bags inflate with great force and will interact with any object in the deployment
zone. Therefore, to reduce the risk of injury to vehicle occupants, GM recommends
that the air deployment zone be kept free of any equipment. If a piece of equipment
were to become dislodged it could strike an occupant in the vehicle and result in
injury. The likelihood of an object becoming dislodged is influenced by many factors,
including the proximity of the object to the inflatable restraint, the size and shape of
the object, and the means by which the object is secured to the vehicle. In addition to
these factors, the trajectory and velocity of a dislodged object can be influenced by
the type and severity of vehicle crash.
Objects that are in the deployment zone, but do not become dislodged by an inflating
air bag can still affect the performance of the air bag. For example, such objects could
tear the fabric or affect the shape of the air bag, thus reducing the ability of the bag
to provide restraint.
Is it possible to shield equipment that is installed in the passenger
side frontal air bag deployment zone in a manner that will allow
full and safe air bag deployment?
Due to the complexity of influencing variables, GM is unable to evaluate the potential
for shielding expected equipment configurations in all accident scenarios in order
to assure that the air bag performance would be unaffected. While shielding may
protect certain equipment from being damaged or dislodged, it may also negatively
affect the inflation characteristics of the air bag. The air bag’s shape, inflation angle,
fold pattern, and inflation rate and pressure are developed to maximize the
protection capability of the inflatable restraint system. Therefore, GM cannot
recommend the placement of any equipment in the deployment zone, even if it is
shielded to protect it from damage.
Front air bag systems and instrument panel mounted equipment.
Passenger air bags in GM vehicles deploy in different ways depending upon the type
of vehicle and the particular instrument panel design.
In some vehicles, the passenger air bag deploys through a discrete door located on
the top surface of the instrument panel (top-mount air bag systems). In other
vehicles, such as the Chevrolet Tahoe, the passenger air bag deploys through a
discrete door mounted on the vertical rearward surface of the instrument panel,
above the glove box door (mid-mount air bag system). With these types of top-
mount and mid-mount passenger air bag systems, the top pad of the instrument
panel remains in place during deployment.
Some GM passenger air bag systems, like the system in the Chevrolet Impala, deploy
from beneath the instrument panel top pad. These are considered 3/4-mount air bag
systems with a
“
deployable top pad.
”
The entire instrument panel top pad is the
“
deployment door
”
from under which the inflating air bag emerges. When an air bag
deployment is commanded, the forces from the inflating passenger air bag push up
on the instrument panel top pad, releasing special fasteners across the rearward edge
of the top pad. This allows the top pad to rotate upward so that the passenger air bag
may emerge. The top pad rotates upward to open widest at the right hand side, and
is usually forced upward into contact with the windshield on the right hand side of
the vehicle during a deployment.
Instrument panel top mounted special equipment, such as a radar antenna and
control unit or video camera must be positioned to the left of the vehicle center line.
This equipment must be mounted as low as possible and securely fastened to the top
pad to avoid being dislodged in the event of a crash and possible air bag deployment.
In the process of securely fastening special equipment to the top, DO NOT fasten
down the top pad itself to any other vehicle component such as the cluster trim plate.
As described above, the top pad rotates upward during a deployment. In order to
enable the proper deployment of the passenger air bag, specialty equipment
installation MUST NOT PREVENT the top pad from rotating upward during
deployment. Location and attachment of special equipment should minimize added
resistance or interference to upward rotation of the top pad during deployment.
Optional side air bags for crashes to the vehicle sides.
The air bag system in your police vehicle may include optional side air bags for front
and rear occupants. Most front-to-rear side air bags are designed to deploy
downward from the interior roof sides to the bottom of the door windows.
can Specialty Vehicle Security Barriers be mounted within the side
air bag deployment zones?
No. The side air bags inflate extremely fast because of the nature of side crashes to
the vehicle. Mounting a security barrier behind the front seats with the ends placed
within the side air bag deployment zones will result in unintended interaction
between the barrier and the inflating side air bags. To reduce the risk of injury to the
vehicle occupants, GM recommends that the side air bag zones be kept free of any
customer installed equipment.
customer furnished equipment installed to the vehicle roof.
Your police vehicle is designed with an interior roof cover system which includes
internal components for the interior lamps and wiring. The roof system may also
include optional side air bag components. Inflation devices may be mounted on the
vehicle roof side behind the rear doors as well as air bag tethers retained to the
windshield pillars. Care must be taken to avoid damage to these components
or interference with their operation when installing roof mounted equipment such
as emergency lamps and communication antennas.
Recommended GM service procedures must be followed to remove
and re-install the instrument panel top pad to ensure that the top
pad will release properly in the event of a passenger air bag
deployment
.
On the right half of the top pad closest to the passenger air bag module,
GM recommends that no equipment be mounted. When mounting equipment on the
driver side of the top pad, GM recommends that the total mass of the top pad
mounted special equipment not exceed 8 pounds (3.6 kilograms), since the top pad
tends to rotate about the left end.
Fasteners used to secure special equipment to the instrument panel top pad, the
windshield glass, or to the windshield upper frame (header), should be selected to
ensure that these devices will remain attached during a vehicle crash and possible
air bag deployment.
Head curtain side air bags are designed to help reduce the risk of head and neck injuries to front and rear seat occupants on the near side of certain side-impact collisions. Always
use safety belts and the correct child restraints for your child’s age and size, even in vehicles equipped with air bags. Children are safer when properly secured in a rear seat. See
your vehicle Owner’s Manual and child safety seat instructions for more information.
