OK, I'm missing something basic here.
Background info: 1985 300TD-T.
A week or so ago, I noticed the left rear window wasn't working. I swapped out the console switch with a spare. That switch made it go down, but I needed to hit the rear switch to make it go back up. On the test switch, the driver's front window wouldn't work, so I put the rear window up and reinstalled the original console switch, and ordered a replacement.
While waiting on the replacement, my wife informed me that the driver's front window suddenly stopped working.
Got the new switch, and it fixed neither problem.
Got to checking around, pulling the door panel, etc. and had power/ ground in all the right places at the right times. Pulled the motor, smacked it. it started working for a minute, then stopped. Pulled it out and apart- corroded inside. Ordered another one.
Driver's rear window- I have power all over, but flicking the switch either way only grounds the motor so it will go UP. I went to pull the rear door switch on the other working rear window to test it on the one that wouldn't work. Couldn't get it out of the surround. Then, suddenly, THAT window started exhibiting the exact same same symptoms- both up and down modes grounded the same side of the motor.
Ordered two rear switches, and another console switch for the left, just to be sure.
Got the parts today. Installed the LF motor, and that fixed that issue. Installed a new RR switch, and that fixed THAT issue. Installed the new LR switch and new L console switch... no workee. Same thing as before- both the console switch and the rear door switch ground the same side of the circuit in both directions, and the window won't move.
I discovered that the brown wire in the rear switch plug had no continuity to ground. So, I used a jumper wire to ground it, and that makes the window go UP but not DOWN.
I have power on both sides of the window motor as I should, but I can only make the window go up. I pulled the new switch on the right rear window to test it on the left rear. No change. The switch for the left rear works fine on the right rear window.
I'm using a W123 wiring diagram that has no bearing on this car- must be the first design and a W126 wiring diagram that seems "close", and everything looks correct. I just can't make the damn thing WORK! Does anyone have the correct diagram for a late 123? Any suggestions? Run into this before?
I power the window motor manually and it goes gangbusters in both directions.
Any ideas?