Adam,
Try calling Beckmann Technologies in Durham, NC at 1-800-742-1021 and get a rebuilt unit. Junkyard electronic parts are always hit or miss and I'm sure you don't want that kind of reliability factor in your Benz. Bob has always done excellent work for me and has a good reputation. He may even have the unit you need in stock and can ship right away, then you return your core for credit.

TobiasMB
4 MBs