I've run my '85 W123 TD thru many a hi pressure was and not had this happen. I do know, from first hand experience that trouble-shooting this electrical problem can be frustrating. The front left/rear right windows are on the same circuit. My first guess is you just blew the fuse, if not then open the door panels and disconnect switches (following the elctrical schematic) until you can isolate the problem area/part.
Also, check the condition of the wiring coming into the rear door from the center pillar...if this is worn from use it could have formed a short.

good luck;

83 W123 300D
All my power windows were working. I took the car to a car wash, the type where one wields a hi-pressure hose to wash the car. Now the front pass side and the rear driver side don't even twitch when using the PW. What'd I do? Is this style of car washing known to cause this kind of problem with the old seals? I'm guessing I'll have to remove the door panels to check out what might have happened. Anybody had this happen to them? Will it dry out and cure itself? How difficult are these door panels to remove.
Thanks Much.