Impact Sensor: Description and Operation

PURPOSE
The air bag system is designed to:
- operate in frontal or front-angled collisions.
- activate the air bags in a crash with severe frontal deceleration, more severe than hitting a parked car of similar size and weight head-on at about 45 km/h (28 mph).
- sense the severity of the crash rather than vehicle speed, thus some frontal collisions at speeds above 45 km/h (28 mph) may not be severe enough to require air bag inflation.






OPERATION
The sensor is an electrical switch which operates as follows:
- It 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.

The sensors in the vehicle determine if air bag inflation is required in the following manner:
- During severe frontal deceleration caused by an impact that decelerates the vehicle in the forward direction, both a primary crash sensor and a safing sensor will activate.
- When a primary and safing sensor are closed at the same time, electrical current will flow igniting the air bag(s).

The primary sensors determine the crash severity while the safing sensor confirms the crash. The safing sensor is used to prevent inadvertent deployments possibly caused by a malfunction in the primary crash sensor circuits or crash sensors.

LOCATIONS
Three sensors are mounted in the vehicle. Their locations are as follows:
- a primary crash front air bag sensor and bracket at the RH front support
- a primary crash front air bag sensor and bracket at the LH front radiator support.
- a safing sensor and bracket at the RH kick panel in the passenger compartment. The safing and one of the primary crash sensors must be activated simultaneously to inflate the air bag.