1995 Lexus SC 400 Air Bag Sensors

I am repairing a 1995 Lexus SC400 which had a minor driver's side front end collision. Both air bags deployed. After removing the front fender, I removed the driver's side air bag sensor. The sensor appears intact save the plastic case is slightly deformed where it was impacted by a bolt end and the filler material has a surface crack. Also, if you shake it, something is loose inside. I understand it is appropriate to replace sensors after air bag deployment but was curious to learn how one trouble shoots these sensors. Also, when installing a replacement unit, how important is the sensor's orientation to motion, ground height, etc? Lastly, if a sensor is faulty, would new air bags deploy (eventhough no collision) because of the faulty sensor or just display an "Air Bag" message on the instrument cluster? Have a good day.