Electrical System

The supplemental air bag restraint system (SRS) is powered directly from the battery. The supplemental air bag restraint system can function with the ignition switch (11572) in any position, including OFF and LOCK. The supplemental air bag restraint system can also function when the front seat (60012) is unoccupied. The electrical system performs three main functions:

• Detects impacts
• Supplies electric power to the igniter(s)
• Monitors the system to determine system readiness

The electrical system components include:

• Air bag diagnostic monitor (14B056)
• Air bag indicator
• Wiring harness and air bag sliding contact (14A664)
• Sensors:
• Primary crash sensor and bracket
• Safing air bag sensor
• The igniter within the driver side air bag module (043B13)

Sensors

 WARNING: VEHICLE SENSOR ORIENTATION IS CRITICAL FOR PROPER SYSTEM OPERATION. IF A VEHICLE EQUIPPED WITH A SUPPLEMENTAL AIR BAG RESTRAINT SYSTEM HAS BEEN INVOLVED IN A CRASH WHERE THE RADIATOR SUPPORT, FRAME RAILS OR COWLS HAVE BEEN DAMAGED, INSPECT THE SENSOR MOUNTING BRACKETS FOR DEFORMATION. IF DAMAGED, THE SENSOR SHOULD BE REPLACED WHETHER OR NOT THE AIR BAG IS DEPLOYED. IN ADDITION, MAKE SURE THE BODY STRUCTURE IN THE AREA OF THE SENSOR MOUNTING IS RESTORED TO ITS ORIGINAL CONDITION.

NOTE: Undamaged sensors will reset automatically after an accident and can be reused.

The sensors are electrical switches which react to impacts according to direction and force. Sensors discriminate 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.

Three sensors are mounted in the vehicle. Their locations are as follows:

• A primary crash sensor on the left-hand side of the radiator support.
• A primary crash sensor on the right-hand side of the radiator support.
• A safing sensor at the right B-pillar.

At least two sensors (one primary sensor and one safing sensor) must be closed to inflate the air bag.

The sensors automatically reset after a collision and do not need to be replaced unless they are physically damaged. Replace only if proper alignment is not possible due to bent brackets, cut wires, smashed connectors, etc.

Air Bag Indicator

The air bag indicator will light continuously for approximately six seconds whenever the ignition switch is turned from OFF to RUN if the air bag is working properly. If system fault is present, the indicator will either fail to light, remain lit continuously or light in a flashing manner. The flashing manner may not occur until approximately 30 seconds after the ignition switch has been turned from OFF to RUN. This is the time required for the air bag diagnostic monitor to test and verify any and all system faults. If the air bag indicator is inoperative and a system fault exists, a tone will sound signaling that the air bag indicator is inoperative and a system fault exists. Refer to the Diagnosis and Testing portion of this section.

Tone Generator

The air bag indicator is the prime means of determining the supplemental air bag restraint system status. However, if the air bag indicator is inoperative and a system fault exists, a tone will sound in a pattern of five sets of five beeps. If this occurs, the air bag indicator will need to be serviced before further diagnosing and testing can be completed. Unless serviced, the supplemental air bag restraint system may not function properly in the event of an accident.