When I bought my '96 used, the OD "off" light would not come on, as well. The switch did work, though. Like everything else that doesn't work, the first thing I did was take it apart to see what was in there.
I disassembled the switch and found that the lamp tested good. I put it all back together and it has worked for the last five years. Apparently, something was not making contact, but I can't say exactly what the problem was.
Bob