Can I fix my light dimmer rheostat
 

After some help please. My light dimmer on my dash is not working. Does anyone know how I can diagnose this and if it is repairable given they are extremely expensive? I turn the knob form side to side and get no change in illumination...

Find some help here?:

http://forums.pelicanparts.com/porsche-911-technical-forum/743037-dim-instrument-lights.html

I had what sounds like the same problem. If it's like mine was - use a flat screw driver to pry out the "lights" plastic center from the rubber on the face of the switch -- behind it there's a screw that you can tighten. This did the trick on mine.

Mine didn't work when I bought it. I pried off the cap from the nob and saw it was missing its retaining nut. Slipped it on and poof, problem solved. Hope yours is that easy