2006 jeep commander airbag light?

I have a 2006 Jeep Commander 3.7. The airbag warning light in the instrument cluster has been coming on recently. It takes about 15 minutes of driving before the light will illuminate. Once the Jeep is turned off and restarted the light goes off and will not return for another 15 minutes. This is NOT the penger airbag off light, its the normal airbag sensor light that comes on for a few seconds when starting the car. Any ideas what this could be?