it's still a good question...the airbag sensor is a internal thing F5 could explain a lot better than i , and agreed the other vehicle went home all butt hurt :wink:
Only air bag sensors are in the bottom of the B-pillars for side air bags, and these are crash type sensors that set off the bag when crushed. Two sensors up front are for determining the stage of air bag deployment. The actual determination to blow are set off by the sensing and diagnostic module, located under the console, (AKA the black box, that is actually silver). There is also the infamous roll over sensor that sends a signal to the SDM to set off both side air bags if there is an indication of a possible rollover. And we know all about the problems this sensor can cause when offroading.
There is also some other misc. sensors and/or switches.
Passenger sensing sensor in the seat to determine if the passenger side air bag is activated in a frontal crash.
Seat position sensor that will trigger an input if the seat is really close to the dash. This prevents a stage two activation of the front bag. For tall people, the normal blow is a stage one (not that explosive), and if it is determined by the SDM via its own programming and the front sensors, it can go into a more explosive stage two activation. You don't want a stage two blow if granny is driving and her nose is one inch from the steering wheel. :giggle:
Also, in a frontal crash, the shoulder belt activator will blow and the belt will cinch up tighter, so make sure you aren't scratching your boob with your arm under the shoulder belt when you have a crash.:giggle: