The safing sensor is located behind the kick panel on the passenger side, below the instrument panel. The safing sensor operates identical to the crash sensor, except for the calibration. This is accomplished using a slightly weaker bias magnet. If the safing sensor contacts close simultaneously with the crash sensor, the air bag(s) will be deployed.
The safing sensor is essentially a safety for the air bag system. It protects the bag(s) from deploying due to an electrical short. The safing sensor is used to verify the force of a collision and complete the air bag(s) deployment. The sensor is located inside the passenger compartment so that a forceful enough impact could be detected, and a false signal from the crash sensor would not deploy the air bag(s) at an inappropriate time.