GMC 2004 Savana - Manual (Page 79)

Seat Position Sensors
Vehicles with dual stage air bags are also equipped with
special sensors which enable the sensing system to
monitor the position of both the driver and passenger
front seats. The seat position sensors provide
information which is used to determine if the air bags
should deploy at a reduced level or at full depoyment.
Air Bag Systems
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.
Inflation is determined by the angle of the impact
and how quickly the vehicle slows down in front or
near-frontal impacts.
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. 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 and in the instrument
panel in front of the right front passenger.
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. Air bags supplement 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 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 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.
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