Impact Sensor: Description and Operation

WARNING: VEHICLE AIR BAG SENSOR ORIENTATION IS CRITICAL FOR PROPER SYSTEM OPERATION. IF A VEHICLE EQUIPPED WITH AN AIR BAG SYSTEM HAS BEEN INVOLVED IN A CRASH WHERE THE FRONT FENDERS OR RADIATOR GRILLE AREA HAVE BEEN DAMAGED, INSPECT THE AIR BAG SENSOR MOUNTING BRACKETS FOR DEFORMATION. IF DAMAGED, THE AIR BAG SENSOR SHOULD BE REPLACED WHETHER OR NOT THE AIR BAG IS DEPLOYED. IN ADDITION, ENSURE THAT THE BODY STRUCTURE IN THE AREA OF THE AIR BAG SENSOR MOUNTING IS RESTORED TO ITS ORIGINAL CONDITION.

The two front air bag sensor and brackets are located at the front of the vehicle behind the radiator grille.

The front air bag sensor and brackets each consist of:
- Sensing mass
- Bias magnet
- Cylindrical tube
- Electrical contacts

During normal operation, the bias magnet holds the sensing mass in place against the magnet. The two electrical contacts remain open during normal operation. Upon impact, the sensing mass pulls away from the bias magnet and rolls down the cylinder toward the electrical contacts. When the sensing mass hits the electrical contacts, it completes the front air bag sensor deployment circuit.