What Makes An Airbag Inflate - Chevrolet 2008 Silverado 1500 Pickup Owner's Manual

Vehicles with dual stage airbags also have seat position
sensors which enables the sensing system to monitor
the position of the driver's seat. The seat position sensor
provides information that is used to determine if the
airbags should deploy at a reduced level or at full
deployment.
Your vehicle may or may not have roof-rail airbags.
See Airbag System on page 1-69. Roof-rail airbags are
intended to inflate in moderate to severe side crashes.
In addition, these roof-rail airbags are intended to inflate
during a rollover or in a severe frontal impact. Roof-rail
airbags will inflate if the crash severity is above the
system's designed threshold level. The threshold level
can vary with specific vehicle design.
Roof-rail airbags are not intended to inflate in rear
impacts. Both roof-rail airbags will deploy when either
side of the vehicle is struck, or if the sensing system
predicts that the vehicle is about to roll over, or in
a severe frontal impact.
In any particular crash, no one can say whether an
airbag should have inflated simply because of the
damage to a vehicle or because of what the repair costs
were. For frontal airbags, inflation is determined by what
the vehicle hits, the angle of the impact, and how quickly
the vehicle slows down. For roof-rail airbags, deployment
is determined by the location and severity of the side
impact. In a rollover event, roof-rail airbag deployment
is determined by the direction of the roll.
What Makes an Airbag Inflate?
In a deployment event, the sensing system sends an
electrical signal triggering a release of gas from the
inflator. Gas from the inflator fills the airbag causing the
bag to break out of the cover and deploy. The inflator,
the airbag, and related hardware are all part of the airbag
module.
Frontal airbag modules are located inside the steering
wheel and instrument panel. For vehicles with roof-rail
airbags, there are airbag modules in the ceiling of the
vehicle, near the side windows that have occupant
seating positions.
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