I noticed when I was driving to Athens, GA a few weeks ago that my odometer isn't working. I looked at online manuals on fixing it myself, but I fear messing up and having to replace the thing completely. Is it worth to go for it myself? How much are they usually worth? I figure they differ from model, I have a 1996 Sentra GXE. How much do they charge at shops normally? My fear is I try to fix it myself and I mess up somewhere or do it wrong and not fix it.