If you are talking about the reverse lamps switch it's a white switch wrapped on the on the column about 8-10 inches up away from the firewall (under the dash). It's adjustable so give it a few turns to the right before thinking it's bad.
If it needs to be replaced it's $9 at AutoZone (DR 403 is the part #), so it's no biggie. I just replaced mine.
The switch looks like this: