Originally Posted by Clemson88

I put a 1984 om617 in my 85 380SE body after removing the gas engine, transmission and differential yoke. I had both automobiles complete and just wanted the wonderful 617 in a black body.

So yes, I can imagine what the wiring might look like behind the gauge cluster. I tracked and diagrammed each wire on both bodies to compare them and removed anything from the 84 body that was needed to install with the diesel engine in the black car.

The service manual electrical diagrams were identical for the gauge and ignition but the few differences I found, glow wiring and such I robbed from the white car and routed exactly as was designed to go. I had the pleasure of completely removing the fuse box housing so I could fish the wires through the firewall in exact location as where the factory would have put them had the SE body been an SD body.

I used the Factory service manual like a bible. I suggest you use it as reference to solve your problems. It has a section on electrical trouble shooting and you're going to have to figure all this out for yourself.

I would say whoever installed that engine in your car was not prideful in his/her/its work as was acceptable in polite company.

My best to you,

https://www.*********.co/misc/Manuals/Servicev3.2/W126-1/Main.html