W123 300D Window Lift

You need both switch to make that window work.

Well, I took the switch connection off left-rear switch and put it on the driver's window switch and activated the switch--the passenger- side window went down and up, no problem, and from that I deduced that the switch itself was OK. I also tested the positive-side switch wire for the driver's side and discovered current there. But window is still all the way down, and every attempt to activate the switch results in a blown 15a fuse for the window pair.

I would do two things...

1. Take apart switch and clean all contacts inside... 6 contacts. This make sure it is not the carbon deposit that is blocking current to the motor... which also increases the current draw.

1. Take apart that door panel and make sure it is not jammed. It is possible that that motor is now too old and draws too much current... so a new motor is your best bet.

Tiger, thanks. The problem turned out to be the positive switch wire. At some time or other, that wire's insulation was stripped too far away from the small wire connector that fits into the switch pot, allowing the wire to come into contact with another terminal or something in the switch--causing it to short. I fixed that, and got everything back together with the right terminal connections, and the window now works flawlessly like it did before.