In a recent thread, one fellow fixed it by just spinning the fuses. Check your seat belt buckle connections for any crap that might have fallen in there. If you can correlate the light with turning the steering wheel then it might be the horn hub under the steering wheel. It's rather expensive so just getting in there and cleaning the area and the contacts might do the trick. With my fault there was nothing visually wrong with the hub but replacing it solved the problem. Try new contacts first, they are inexpensive.

glenmore
1991 300CE
2000 C280