Air Bag Resistor: Description and Operation

The SIR Resistor Module is inserted in the SIR harness between the Inflator Module and the DERM. The SIR Resistor Module allows the DERM to monitor the deployment loop for faults and also allows the DERM to detect when a deployment has occurred.
The resistors in the SIR Resistor Module are balanced with the resistors in the Arming and Discriminating Sensors. This allows the DERM to monitor the voltage drops across the deployment loop components. Faults are detected during normal non-deployment conditions by monitoring these voltages.