Are seat belts supposed to lock on all car crashes? On my 03 mazda 6 were my air bags supposed to go off if I got rear ended so bad the person smashed the whole back end of my car?

There is a mechanism in the seat belt assembly that momentarily locks the seat belt position, when there is a sudden movement to it. After impact, most will release. That is to keep you from moving forward, after impact with an object. The latch mechanism is never permanently locked. You just press the release, and get out of the belt. ---- The airbag is designed to only inflate in moderate to severe frontal crashes...however, if you have a car equipped with side curtain airbags, I believe these should deploy in a collision to either side of the car. I don't believe most airbags are designed with rear collisions in mind, but I could be wrong-----

Unless that rear collision causes the front of your car to hit something, would be my guess.

I got rear ended and I hit my stealing wheel and got bruised up pretty bad on my left arm, I was wondering if I got hit so hard why didn't my air bag go off or my seat belts lock, I rather have a belt mark across my chest than almost dislocating my shoulder on the steering wheel. The person hit me so bad my car is totaled and my truck is so smashed my car stops at the backseat.

I got rear ended and I hit my stealing wheel and got bruised up pretty bad on my left arm, I was wondering if I got hit so hard why didn't my air bag go off or my seat belts lock, I rather have a belt mark across my chest than almost dislocating my shoulder on the steering wheel. The person hit me so bad my car is totaled and my truck is so smashed my car stops at the backseat.

Air Bags are for Frontal Impacts. In most cases, if you're wearing your seatbelt and get hit - the Air Bags don't do anything anyway. The side Bags will help in a side impact but from the rear - there's almost nothing except the seat belt.