Arming Sensor/Dual Pole Arming Sensor

WARNING: This page is about a different car, the 1994 GMC Safari and 1994 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.

Arming sensor/dual pole arming sensor is a protective switch located in power feed side (positive side) of deployment loop. It is calibrated to close at low-level velocity changes (lower than discriminating sensors). This assures that each inflator module is connected directly to 36VLR output of DERM or ignition voltage when either of the discriminating sensors close.

Arming sensor/dual pole arming sensor consists of a sensing element, normally open switch contacts, a diagnostic resistor and 2 diodes. Sensing element closes normally open switch contacts when velocity of vehicle changes at a rate indicating potential need for deployment. A diagnostic resistor is connected in parallel with normally open switch contacts and allows for a small amount of current flow through deployment loop during normal undeployed conditions. This small current flow results in voltage drops across each component within the loop.

DERM monitors these voltage drops to detect circuit or component faults. The 2 diodes provide isolation between 36VLR output of DERM and ignition voltage. In some vehicles, arming sensor is combined with passenger compartment discriminating sensor.