I have an Eclipse AVN5495 and the volume UP part of the button does not work very well. Sometimes it'll work perfectly, but more often than not, I have to press extremely hard for it to change. Down works perfectly.

Any idea on how to fix this??

 

Not a fix, but you could always by the remote.

 

You could try taking the headunit apart and seeing if the button is stuck, but that would void the warranty

 

If you're out of warranty, and handy with a soldering iron you could likely order the micro switch and button from a parts supplier.

I used to repair decks from time to time and got most of my pieces from http://www.pacparts.com/

 

I would like to sell the unit, so the remote isn't really a good option for me. And the warranty is long gone probably, so that's not an issue.

I'm not very handy with a soldering iron, but I think I can do a simple thing like that. I assume I would have to completely remove the unit from the car to open it up?

 

Yup, it'd have to come out before you can do anything (no detachable face on Eclipses last i knew).

First step would be to call Eclipse (fujitsu-ten) and ask for a phone # for their parts supplier so you can buy a microswitch and the plastic button. with both those in hand, you should be set to start disassembling.