We have seen 2 early W124's melt dash wiring harnesses.
Not clear on where it started-- but the smoke/smell desription concerns me.
Grounds were clean and tight.

Both of these cars had electrical draws, and lost various dash/a-c/radio functions.

Not an insulation degradation like the engine harnesses of later years.

These harnesses melted into a a big,charred black wad of goo behind the instrument cluster.

Replacement harness was in excess of $1000 for the parts, plus a heap of labor.

Both are still on the road todaym with no further electrical problems.

__________________
Todd Haven
Parts Manager
MPH Automotive
Houston,TX