For 1990-2009 cars

The Supplemental Inflatable Restraint (SIR) system supplements the protection offered by the driver and front passenger seat belts. The SIR system deploys an air bag (3) from the center of the steering wheel and from the right side of the instrument panel.

A frontal crash of sufficient force up to 30 degrees off the center line of the vehicle will deploy the air bags. The knee bolsters (2) absorb crash energy. The driver and passenger knee bolsters are below the instrument panel. The steering column is collapsible.

The SIR system consists of the following components:

• | An Inflatable Restraint Sensing and Diagnostic Module (SDM)

• | An Inflatable Restraint Steering Wheel Module

• | An Inflatable Restraint Steering Wheel Module Coil in the turn signal switch assembly

• | An Inflatable Restraint IP Module

• | An AIR BAG warning lamp in the instrument cluster

The deployment loops consist of the following parts:

• | The SDM

• | The inflatable restraint steering wheel module coil

• | The inflatable restraint steering wheel module

• | The inflatable restraint IP module

• | The connecting wires

The function of the deployment loops is to supply current through the inflator modules, which will cause deployment of the air bags. Deployment occurs when the SDM detects sever vehicle velocity changes.

The SDM contains a sensing device (Accelerometer) that converts vehicle velocity changes into an electrical signal. The SDM compares this electrical signal to a value stored in memory. When the generated signal exceeds the stored value, then the SDM performs additional signal processing and compares the generated signals to values stored in memory. When two of the generated signals exceed the stored values, then the SDM will cause current to flow through the inflator modules, deploying the air bags.