X2 on KDX's diagnosis. Replace the sender, and I'm sure you will be happy. I have not heard of very many of these going bad, so a junkyard might be your cheapest option. A layer of varnish on the contacts may be your problem, so it may also be possible to clean them (don't quote me on that, as I've not seen the actual part, only others - just a thought). If that is possible, a can of electrical contact cleaner would be the best to use.
