I just finished rebuilding my engine (M119) wire harness from scratch last weekend. I learned how to solder on youtube. I got the wire from amazon. I got a headache from trying to figure out which wire went to which connector. Thankfully, another member of this forum sent me his old harness to use as a model, and this also provided me with some of the plugs. All in all, it was a really large undertaking for me, and I am used to doing complicated work. It is amazing what a difference the new harness made. Now it is very powerful and very smooth, like a 400E should be. Total cost: $75.00

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1992 400E current
1988 300E sold
1973 280C totalled
1973 280SEL never got it running
1971 250C my first love but rusted out