I have exactly the same problem with my '95 300D! Last week I had the car in for brake pad replacements and after they washed the engine, the AC stopped cooling. The compressor would kick off after about 2 seconds. After all dried out, it was OK.

I first experienced it after washing my car a few months ago and then in an extremely heavy rain fall. There is a panel in the back of the engine compartment , passenger side, that houses a lot of wiring that was sourced to be the problem when wet...

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Mark Herzig
1995 E300D 153K
1985 300D 142K (sold)
1979 450SL 122 miles (sold)
1992 500E 127K (sold)
1987 300SDL 132K (sold)
1986 300E 161K (sold)