Air Bag Indicator

The air bag indicator is controlled by either of the following components:
^ The inflatable restraint Sensing and Diagnostic Module (SDM)
^ The instrument cluster

The SDM sends a Class 2 message through circuit 1036 to the instrument cluster to turn on the indicator when a problem with the SIR system has been detected.
The instrument cluster turns on the air bag indicator under the following conditions:
^ Class 2 communication has been lost between the instrument cluster and the SDM.
^ The 3 second bulb test is occurring.

If the instrument cluster detects a fault in the air bag indicator, the cluster sets DTC B0670 and illuminates the Service Vehicle Soon indicator.