Discriminating Sensors

There are two discriminating sensors in the air bag system. They are wired in parallel on the low (ground) side of the deployment loop. These sensors are calibrated to close with speed changes severe enough to warrant deployment.
A diagnostic resistor is connected in parallel with the switch contacts within each of the discriminating sensors. These parallel resistors supply the ground path for the current passing through the deployment loop during normal operation. This current flow results in voltage drops across each component in the deployment loop. The DERM monitors these voltage drops to detect malfunctions.