One problem related to air bag light on has been reported for the 2005 Mazda RX8. The most recently reported issues are listed below.
Driver was backing out of a parking space when an extremely loud pop sounded resembling a backfire or the explosion of an aerosol can. After pulling back into the space, a further inspection of the noise revealed a malfunction with the rear passenger seat airbag. The door panel has been knocked askew resulting in a back door that will not open. The front seat passenger seat belt was jerked tight and remains completely locked up. Had a passenger been sitting in the front seat, the tightening of the belt upon the malfunction of the airbag would have resulted in injury. The other airbags are of great concern at this point because if there is another malfunction when the car is in motion on the road, serious injury would occur. The airbag indicator light continues to either blink or remain constantly lit. The problem has not yet been addressed with the dealer as I'm guessing it will be very costly to fix.