Air Bag Control Module: Description and Operation
DESCRIPTIONThe Sensing and Diagnostic Module (SDM) performs several system functions. These functions include energy reserve, air bag deployment, malfunction detection, malfunction diagnosis, driver notification, frontal crash detection and frontal crash recording.
OPERATION
The SDM is connected to the SIR wiring harness by a 20-way connector. This harness connector uses a shorting bar across certain terminals in the contact area. This shorting bar connects the "AIR BAG" warning lamp to ground when the DERM harness connector is disconnected. This will cause the AIR BAG warning lamp to come on steady whenever the ignition switch is at the Run, Bulb Test or Start positions with the SDM disconnected.