Electrical System

The air bag system is powered directly from the battery (10653) . The system can function with the ignition switch (11572) in any position, including OFF and LOCK. The system can also function when the driver seat is unoccupied. The electrical system performs three main functions:

• Detects an impact.
• Switches electric current to the igniter.
• Monitors the system to determine readiness.

The electrical system components include:

• Electronic air bag diagnostic monitor with integrated backup power supply.
• Air bag system readiness indicator.
• Wiring harness and air bag sliding contact (14A664) .
• RH radiator primary crash front air bag sensor and bracket (14B004) and LH radiator primary crash front air bag sensor and bracket (14B005) .
• Igniter within driver side air bag module (043B13) and passenger side air bag module (044A74) .

Sensors

The radiator primary crash sensor assembly 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.
• The safing sensor and one primary crash sensor must be activated simultaneously to inflate the air bag.

The air bag system is designed to operate in frontal or front-angled collisions. The driver side air bag module and passenger side air bag module should activate 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).

Because the air bag system senses the severity of the crash rather than vehicle speed, some frontal collisions at speeds above 45 km/h (28 mph) may not be severe enough to require air bag inflation.

The sensors in the vehicle determine if air bag inflation is required in the following manner:

1. During severe frontal deceleration caused by an impact that decelerates the vehicle in the forward direction, both a radiator primary crash sensor and a safing sensor will activate.

2. When a primary and safing sensor are closed at the same time, electrical current will flow, igniting the driver side air bag module and passenger side air bag module .

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