Air Bag Systems: Description and Operation
INTRODUCTIONWARNING: Extreme care must be used when servicing the SRS to avoid injury to the service personnel (by inadvertent deployment of the air bags) or the driver (by rendering the SRS inoperative).
The Supplemental Restraint System (SRS) is designed to supplement the driver's and front passenger's seat belts to help reduce the risk or severity of injury to the driver and front passenger by activating and deploying both front air bags in certain frontal collisions.
The SRS consist of two air bag modules, SRS air bag control unit (SRS-ECU), SRS warning light, and clock spring. Air bags are located in the center of the steering wheel and above the glove box. Each air bag is made up of a folded air bag and an inflator unit. The control unit under the floor console monitors the system and has a safing G-sensor and an analog G-sensor. The warning light on the instrument panel indicates the operational status of the SRS. The clock spring is installed in the steering column. Only authorized service personnel should do work on or around the SRS components. Those service personnel should carefully read before starting any such work.
SRS Air Bag Special Connector:
SRS AIR BAG SPECIAL CONNECTOR
To enhance the system reliability, a connector lock switch is integrated in the SRS-ECU connector, the air bag module connectors, the clock spring connector (black connector "A" shown in the illustration below).
Squib Circuit Connector Lock Switch:
SQUIB CIRCUIT CONNECTOR LOCK SWITCH
The switch is a mechanism that shorts the power supply terminal to the ground terminal automatically in the air bag squib circuit when the connector is disconnected. A "short" spring is integrated inside the connector. This spring prevents static electricity from flowing to the squib by shorting the power supply terminal to the ground terminal (i.e. there is no potential difference between the two terminals).
CAUTION: When the connector is disconnected, there will be short circuit between the terminals This is not a fault.
WARNING LIGHT CIRCUIT CONNECTOR LOCK SWITCH
The switch is a mechanism that shorts the power supply terminal to the ground terminal automatically in the warning light circuit when the connector is disconnected. Its structure is similar to the squib circuit connector shorting mechanism.