Electric window lift--problem
 

Yesterday I lowered all the windows in my '82 300SD to let out the hot air from the car sitting in the sun. Then I tried to close all the windows. RR and LF would not close. The fuse box identified fuse "a" as contolling those 2 windows. I replaced fuse "a" and the LF worked fine. The RR still was down. I pulled the door swicth and found I had power there, so i jumpered the terminals to get the motor to run, and I got the window closed.
Now my question.
How do I determine the fault in the circut? Is it most likely that the RR switch is bad? Does disassembling them for cleaning help, or is it likely that there is another cause?
Thanks.

Try swapping the RR switch with the LR. If it's the switch, this should tell you in a minute....

I would bet on a good switch cleaning first. It should be listed as mandatory maintenance :D Often pondered why these switches get so grimy and the only sensible reason I could come up with is the rear air duct on the console must cause a lot of grimy air to come across those switches. But I would listen to other peoples thoughts....

I, too , thought it might be the switches, but something troubles me about that. Why would BOTH switches fail at precisely the same time? Is there another possibility that explains the failure of the window to go up? It goes down fine ( RR)

Well, it was the door switch after all. I replaced it with the one from the opposite side and it worked from from the console and the door switch. Then I opened up the bad switch and cleaned the contacts, and it works just fine. Window switches are MUCH simpler than seat switched. If your windows quit, do not be afraid to open up the switch; very simple