Last time I fought issues like yours, I had two intermittently broken wires inside the pillar (85 300SD). My window would go up with the door open, but not closed. By holding the window switch in the up position, and tugging/wiggling the wires going into the pillar, I could get the window to work/fail. I isolated the breaks by sticking a THIN sewing needle into the wire (i.e. thru the insulation, into the conductor) "upstream" of where I though the break was, and metering at the window switch connector in the door. I ended-up splicing-in new segments for the two broken wires. I never had to do this with a w123, so YMMV. Good luck!

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- Nate

'85 300SD (200 kmi), Running on Biodiesel
'83 300D (230 kmi, RIP)
'80 300D (150 kmi, Foster Car)