129 cluster problem
 

i have a 92 500 sl cluster problem. the cluster went dead. the only thing that works is the clock and engine temp. From what i have learned from you guys is that it is a circuit board in the cluster. i think it happened when i jump started the car after it was in storage for 2 years. I had a bunch of problems once i got the car going again. Thanks to this forum and all who contribute to it all the problems were solve. Back to the question at hand. I bought a working kilometer cluster to test all the other problems. Is there any interchangeable parts i can swap out of kilometer cluster into the dead mph cluster to make it work? Or any ideas to get one good mph cluster out of the 2 clusters.

once again thanks

Vikon
Check this first:
Open hood, over on right side of engine bay (passenger side)
way in back by the firewall. Remove the black plastic cover. Under the cover is a computer module box, you'll need to remove the lid from this box. Once that's off, you'll see a module with a small clear plastic cover, and under that cover there are some fuses. Check those fuses. Don't worry about fuses that are missing, if they aren't there they don't belong there.
This module is called the Base Module, BM for short.

Gilly

Gosh, I don't know what parts would be interchangeable, but I'd suspect most of them are the same between the two clusters. Probably different EPROM's for miles verses kilometers. I was cruiseing on ebay in the Mercedes area and noticed a company that is selling rebuilt clusters for 129's. They have an e-mail address, so why not contact them and see if they will either repair, exchange, or use two to make one working unit. There are also other references in this forum to companies in Florida and New Jersey that repair for a flat rate, (which I think is a bit steep). But if they have investments in special instruments or jigs, I suppose they need to recoup a bit.

I really haven't a clue as to the circuitry in the cluster. But if it's a good design, it should not fail when jump starting the car. Geez, we'd be replacing the darn things all the time. I suspect the engineers may have used some protective circuitry as simple as what are called IC fuses. It's a very fast fuse that protects the IC's in the circuit. If it's just a fuse, than paying $275 for a repair ( replace the 75 cent fuse ) seems a bit much.