We had the same problem on my sons 95 convertible. Never could figure out exactly what was causing it, but we did find the box in the dash behind the stereo that makes the dinging. There are 2 plugs on it. Coming from the drivers floorboard, unplug the one closest to thefirewall, and the light will go off and the dinging wll stop.
I know this won't solve the problem, but it will make it a little less annoying until you can get it fixed