I had a similiar problem with an airbag light on my old 2003 sunfire. It would light up usually on trips where i would be going a steady speed.

At the time I had access to some parts cars but no scanners so I just threw parts at it, I ruled out the clockspring, then I replaced the front airbag sensor and that seemed to solve it but i will never know for sure since two weeks later someone cut me off and destroyed the car and deploying the airbags.