AIR BAG MODULE
See Figures 1 and 2
The air bag module is the most visible part of the system. It contains the air bag cushion and its supporting components. The air bag module contains a housing to which the cushion and inflator are attached and sealed.
The inflator assembly is mounted to the back of the module housing. When supplied with the proper electrical signal the inflator assembly will produce a gas and discharges it directly into the cushion. A protective cover is fitted to the front of the air bag module and forms a decorative cover in the center of the steering wheel. The air bag module is mounted directly to the steering wheel.
FRONT IMPACT SENSORS
See Figures 3 and 4
The driver air bag system is a safety device designed to reduce the risk of fatality or serious injury, caused by a frontal impact of the vehicle.
The impact sensors provide verification of the direction and severity of the impact. Three impact sensors are used. One is called a safing sensor. It is located inside the diagnostic module which is mounted on the floor pan, just forward of the center console. The other two sensors are mounted on the upper crossmember of the radiator closure panel on the left and right side of the vehicle under the hood.
The impact sensors are threshold sensitive switches that complete an electrical circuit when an impact provides a sufficient G force to close the switch. The sensors are calibrated for the specific vehicle and react to the severity and direction of the impact.
See Figure 5
The clockspring is mounted on the steering column behind the steering wheel, and is used to maintain a continuous electrical circuit between the wiring harness and the driver's air bag module. This assembly consists of a flat ribbon-like electrically conductive tape which winds and unwinds with the steering wheel rotation.
See Figures 6 and 7
The Air Bag System Diagnostic Module (ASDM) contains the safing sensor and energy reserve capacitor. The ASDM monitors and system to determine the system readiness. The ASDM will store sufficient energy to deploy the air bag for only two minutes after the battery is disconnected. If both front impact sensors are open the air bag could be deployed up to 9.5 minutes after the battery is disconnected. The ASDM contains on-board diagnostics, and will illuminate the AIR BAG warning lamp in the cluster when a fault occurs.
The air bag module must be stored in its original special container until used for service. Also, it must be stored in a clean, dry environment, away from sources of extreme heat, sparks, and sources of high electrical energy. Always place or store the module on a surface with the trim cover facing up to minimize movement in case of accidental deployment.
HANDLING A LIVE MODULE
At no time should any source of electricity be permitted near the inflator on the back of the module. When carrying a live module, the trim cover should be pointed away from the body to minimize injury in the event of accidental deployment. In addition, if the module is placed on a bench or other surface, the plastic trim cover should be face up to minimize movement in case of accidental deployment.
When handling a steering column with an air bag module attached, never place the column of the floor or other surface with the steering wheel or module face down.
The vehicle interior may contain a very small amount of sodium hydroxide powder, a by-product of air bag deployment. Since this powder can irritate the skin, eyes, nose or throat, be sure to wear safety glasses, rubber gloves and long sleeves during cleanup.
If you find that the cleanup is irritating your skin, run cool water over the affected area. Also, if you experience nasal or throat irritation, exit the vehicle for fresh air until the irritation ceases. If irritation continues, see a physician.Clean-Up Procedure
See Figure 8
Begin the clean-up by putting tape over the two air bag exhaust vents so that no additional powder will find its way into the vehicle interior. Then remove the air bag and air bag module from the vehicle.
Use a vacuum cleaner to remove any residual powder from the vehicle interior. Work from the outside in so that you avoid kneeling or sitting in a uncleaned area.
Be sure to vacuum the heater and A/C outlets as well. In fact it's a good idea to run the blower on low and to vacuum up any powder expelled from the plenum. You may need to vacuum the interior of the car a second time to recover all of the powder.Service Of a Deployed Air Bag
After an air bag has been deployed, the air bag module and clockspring must be replaced because they cannot be reused. Other air bag system components are replaced if damaged.