You really need to have the codes checked for a proper diagnosis but there are a couple of common problems that can cause the airbag light that perhaps you can diagnose yourself. The cancellation module/clock spring is a common failure or broken wires to the clock spring in the steering column. The other common possibility is broken wires/loose connection to the side airbag in the front seats(usually drivers). Airbag codes are self correcting/cancelling and that's why the light likes to go on and off. Next time the light is off with the car running try turning the steering slowly back and forth lock to lock and see if you can get the light to come on, that would indicate clock spring fault. Also try running the steering column up and down, in and out and see if the light comes on, that would indicate broken wiring at the column. If neither of those cause the light try moving the seat up and down fore and aft and see if the light comes on, that would indicate loose/damaged wiring for the side impact bag in the seat. All of this is of course an internet diagnosis and no results are gauranteed, just some things to try.