Originally Posted by JHZR2 (Post 2833498)

Two quick questions on this (great DIY BTW).

1) does the black knob have to be pulled off first from the frontside?

Originally Posted by JHZR2 (Post 2833498)

2) not to be too lazy or anything, but if one didnt want to break all the connections and take the risk pulling the cluster, how feasible would it be to unscrew the rheostat from behind and just pull it off with the cluster in place or just pulled out into the gap between its hole and the steering wheel? Sure it is a bit tougher to do it by feel, but there are other benefits to doing it this way.

Thanks!

Originally Posted by mbzjag8090 (Post 2833544)

Any idea if you could do this refurbishment on an 84 W126?

Originally Posted by 240Dpdx (Post 2874412)

Great Post thanks. I just bought an 83 240D and the instrument lights and console lights went out. Originally I thought it was a fuse but none of the fuses seemed to be bad. I actually couldn't figure out exactly which fuse controls those lights - there is one that says inst. clust. but I wasn't sure if that was for the actual gauges or for the lights. At any rate, when I pulled that fuse the gauges stopped working so presumably the fuse was good. Does anyone know the specific fuse for those lights? Since nothing else is not working, it probably is not the fuse but I'd hate to pull everything out just to find out later that it is. Also, in the event that I can't get the rheostat working after I pull it, does anybody know where I can find info on repairing using a jump wire?
Thanks

Originally Posted by tankowner (Post 2833585)

No, there is a metal piece that fits into the plastic knob - it pulls out from behind when you remove the rheostat.



Hmmm, not sure. May be possible, probably not very easy - but I never tried. I think would would at least have to push or pull the cluster out enough to see the rheostat, but probably still tough to get at. It doesn't take too much to disconnect the cluster, just keep track of where eveything goes - draw a simple diagram to help out as you undo things. Or use your camera to snap a couple pics first.

Originally Posted by tankowner (Post 2280527)

My dash and console lights were not working on the '83 240D. After doing some searching I realized that it had to be the rheostat located on the back of the instrument panel. If you own an older MB and none of your dash or console light are working, there's a good chance your rheostat is corroded. What is a rheostat you say? A rheostat is simply a device that allows you to control the resistance in a circuit. In this case, it allows you to control the brightness of the dash lights. Unfortunately, the internal contacts tend to corrode over time and eventually enough corrosion will halt the current flow through the rheostat with the end result being no more lights.

The most common "fix" for a bum rheostat is to simply solder a jumper wire across the two metal strips on the back of the rheostat. This effectively bypasses the internal components, which is good because it gets your lights back. However, in doing so you sacrifice the ability to dim your lights if you want to. The argument for bypassing the rheostat is that, even on "high", the dash lights in these older MB cars are not all that bright. After fixing mine, I agree, but nevertheless, I still wanted to open up the rheostat to see what it looked like inside and, once I did, I realized it wouldn't be a hard fix - so I cleaned up the contacts, put it back together and now it works great. What follows is a DIY on refurbing you dash light rheostat.