The ECU acts like the brain of the air bag system; it receives signals from the various sensors and decides if and when each air bag should deploy.
The ECU is typically located in the middle of the vehicle, where it is well protected.
In advanced air bag systems, the ECU can also receive inputs from additional sensors that detect occupant weight, seating position, seat belt use and seat position to determine the force with which the frontal air bags should deploy.
