3.2 Functional Operation

Whenever the igniton key is turned to the RUN or START position, the "Air Bag" warning lamp on the instrument cluster lights and turns off after 6 to 8 seconds. This means that the air bag system diagnostic module (ASDM) has checked the system and found it to be tee of discernible malfunctons. The air bag electrical system is monitored by the ASDM. The ASDM contains the safing sensor, and integral sensor in the circuitry of the system, that is used to deploy the air bag.

The ASDM monitors critical input and output circuits within the air bag electrical system, making sure they are operating correctly. Some circuits are tested continuously; others are checked only under certain circumstances. The ASDM provides informaton about the air bag system through the "Air Bag" warning lamp and the DRB II (Diagnostic Readout Box II).

The deceleration resulting from the impact of a front-end collision causes the switch inside the ASDM safing sensor to close. As soon as one of the front sensors and the safing sensor are closed, an electrical charge is sent to the air bag module. This causes the air bag inflator to actuate, which produces a quantity of nitrogen gas, thus deploying the air bag. The total time from the closure of the switches to deployment and deflation of the air bag is approximately 1/10th of a second.

The "Air Bag" warning lamp is the only point at which "symptoms" of an electrical system malfuncton can be observed by the customer.

Use the test procedures in this book to find the cause of any customer complaint regarding the *Air Bag" warning lamp, such as:

^ Warning lamp does not come on at all
^ Warning lamp stays on