Air Bag Systems: Description and Operation
The Supplemental Air Bag Restraint System (SRS) is designed to provide increased accident protection for front seat occupants IN ADDITION TO that provided by the three point safety belt system. Safety belt use is necessary to obtain the best occupant protection and to receive the full advantages of the supplemental air bag. FORD RECOMMENDS THE USE OF SAFETY BELT SYSTEMS FOR ALL VEHICLE OCCUPANTS.
The Supplemental Air Bag Restraint System consists of two basic subsystems:
- The driver and (optional) passenger air bags.
- The electrical system; including impact sensors, electronic diagnostic monitor and a backup power supply.
Electrical System
The air bag system is powered directly from the battery. The system can function with the ignition switch in any position, including OFF and LOCK. The system can also function when the driver or passenger seats are unoccupied. The electrical system performs three main functions:
- Detects an impact.
- Switches electric power to the air bags.
- Monitors the system to determine readiness.
The electrical system components include:
- Diagnostic monitor.
- Air bag system readiness indicator.
- Wiring harness.
- Sensors.
- The igniter within the driver and (optional) passenger air bags.
- Backup power supply.
Sensors
The sensor is an electrical switch which reacts to impacts according to direction and force. It discriminates between impacts that require air bag inflation and impacts that do not require air bag inflation. When an impact occurs that requires air bag inflation, the sensor contacts close, completing the electrical circuit necessary for system operation.
Four sensors are mounted in the vehicle. Their locations are as follows:
- A dual crash and safing sensor at the hood latch support.
- A crash sensor at the RH fender apron.
- A crash sensor at the LH fender apron.
- A safing sensor at the LH cowl side in the passenger compartment.
At least two sensors, one safing, one front, must be activated to inflate the air bag.