General Motors calls their air bag system a Supplemental Inflatable Restraint (SIR). Most other Manufacturers refer to it as a Supplemental Restraint System (SRS). SRS is also widely accepted as the industry standard nomenclature for the system. This guide may use SIR or SRS when referring to the air bag system.
The Supplemental Inflatable Restraint (SIR) system helps supplement the protection offered by the driver and front passenger seat belts by deploying an air bag from the center of the steering wheel and from the top of the right side of the instrument panel. The air bag deploys when the vehicle is involved in a frontal crash of sufficient force up to 30 degrees off the centerline of the vehicle. The SIR system consists of the following components:
See Figures 1 and 2
The Sensing Diagnostic Module (SDM) maintains a reserve energy supply with sufficient voltage to cause a deployment for up to ten minutes after the ignition switch is turned "OFF", the battery is disconnected or the fuse powering the SDM is removed. Many of the service procedures require removal of the inflater module fuse and disconnection of the deployment loops to avoid an accidental deployment .
- Turn the steering wheel to the straight ahead position.
- Remove the key from the ignition switch.
- Remove the SIR fuse from the Instrument Panel (I/P) fuse block.
- Remove the left side I/P sound insulator.
- Disconnect the Connector Position Assurance (CPA) and the driver side yellow 2-way connector located at the base of the steering column.
- Remove the right hand I/P sound insulator.
- Disconnect the Connector Position Assurance (CPA) and the passenger side yellow 2-way connector located near the base of the steering column.
With the SIR fuse removed and the ignition switch in the RUN position, the AIR BAG warning lamp illuminates. This is normal operation and does not indicate a SIR system malfunction.
Arming the system
- Connect the Connector Position Assurance (CPA) and the passenger yellow 2-way connector located near the base of the steering column.
- Install the right hand I/P sound insulator.
- Connect the connector position assurance (CPA) and the driver yellow 2-way connector located at the base of the steering column.
- Install the left side I/P sound insulator.
- Install the SIR fuse from the I/P fuse block.
- Staying well away from both air bags, turn the ignition switch to the RUN position. Verify that the AIR BAG warning lamp flashes seven times and then stays off. If the AIR BAG warning lamp does not operate as described, the system will have to be diagnosed.