Thanks to this forum I was able to fix my dark instrument panel lights. My 230sl probably hadn't been driven at night for about 20 years. I had some work done and picked it up after dark, got in, started it up and had a dark instrument panel. I drove home using the flashlight on my iPhone to illuminate the dash. I am a total newbie to car repair, but decided to give it a try.
I researched the problem on this forum and determined it was either the fuse or the rheostat. Confusing the issue, my right license plate light was out, but the taillight was working. So I figured it must be the rheostat. I turned the rheostat back and forth looking for any flicker, but no joy. Following the instruction here, I bypassed the rheostat, and voila! The lights lit up! (Prettier than a Christmas tree on Christmas day!) My soldering skills suck, but practice will help. Took about 2hrs, mainly because my soldering tip was dirty and not working well, but should have taken less than 45 minutes if you have any clue.
Thanks to all the contributors to this forum.
Matt