I too had a 94 124 with a bad wiring harness, and put several weeks, just tinkering, into repairing it. It was great fun and I got it to start again, and it ran fine for about a month, then it failed again at an inopportune time. I came to the conclusion that repair was not viable. Once it is bad enough to short out in one place there are many places that are marginal. And just moving it around to repair is likely to cause more failures. I don't know where you're getting the $900 number but I paid $430 for mine a year ago. MB prices are in the opposite of freefall, but I would think you could find a new one for around $500. Have you tried Caliber? It is unfortunately a MB sourced part.