Wiring harness failures--What models? what years?

[Cal Learner]

I've followed a great many threads involving failure of the main engine wiring harness. Obviously, there was some sort of a shortcoming in the manufacture of the wiring. I've read various speculation that it was the result of using substandard insulation due to strict environmental controls in Germany, etc. Whatever the cause, it is obviously a real problem.

Fortunately, my 1988 W124 (192K miles) has not had a problem with the harness (yet). Can anyone knowledgable about the problem tell me whether it is limited to specific models (or engines) and not to others? To precise model years and not to others? Thanks.