Air bag sing on

I have a Silhouette 2001 and sometimes the Air-bag sign turn on and it lasts for long periods and sometimes it doesn't show anything for days.

I read sometimes about clip under the seat. it worked but it still appers again.

Can anybody help me ?

Thanks

your talking about the light on the dash ,right. mine does the same thing i read some where about it was the clockspring in the steering column under the steering wheel somehow the spring loses contact or something and makes the light come on.i never got around to pulling the steering wheel to see .....