What year did Mercedes start using a computer system?

Well, most manufacturers have been using computers in some form since the 1980's. I would probably go back to a late 1970's model if you wanted something computer-free. That said, I don't think your husband would have any problem working on even early 1990s models, as the computer systems have progressed a lot since the early days. A 1970's Mercedes diesel might also provide an interesting project and one that he could convert to biofuel if he wanted to. These are typically cheap and fairly available. I have seen several here in PA in the past year for $1500-2000.

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