Air Bag Module
WARNING: This page is about a different car, the 1995 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
Air bag module is mounted on front face of steering wheel. See Fig 1 . Module's inflator assembly produces nitrogen gas to fill air bag. When a small amount of current from ASDM is applied, ignitor assembly starts a thermal reaction that spreads an ignitor charge.
Surrounding ignitor charge is a pellet-filled area which produces nitrogen gas. Gas pressure builds and discharges from inflator through a diffuser and screen assembly, forcing steering wheel cover to burst along its seams until air bag is fully inflated. Once air bag is fully inflated, gas escapes from bag away from driver through vents.