I swapped the rear window switches with each other and then swapped the console rear switches with each other with no change in behavior of either rear window motors (i.e., right rear still fine, left rear still goes down but won't go up.) I also removed the left rear door panel and tried to gently tug on the wires while holding the switch for up, but nothing happens.

When I push the up switch I can hear the relay clicking under the rear seat. My hypothesis is that the window motor system thinks the window is already all the way up and won't give the motor any juice. Is there a cut-off switch on the motor that might be bad?

I hate to tear up the flooring of the car looking for a broken wire. It seems to me that it would be a lot easier to check for continuity of wiring using an ohmmeter, but as I mentioned earlier, my wire colors don't match the Haynes schematics and I wonder if MB changed the window system in 1994 (my Hanynes manual is for 1985 to August 93). Plus I don't fully understand how the Haynes diagram would work, especially the switches. Anyway, here are my 1994 E320 left rear switch colors: Pin1-Brown; Pin2 Grey/blue; Pin3 Blue/white; Pin4 Green/red. Haynes is Pin1 green; pin2 Black; pin3 green/red; pin4 brown; pin7 blue/white; pin 58 (the diode?) green/blue.

Any help will be greatly appreciated. My next move is to simply disconnect the left rear window motor wires (you can hardly drive the car with the windows down anyway).

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TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)