This would be my first time...so bear with me. 1987 260E, but should apply to any W124.

I got the panel off and all, found the connector. I saw that it contains a Green + Black connector that leads to the motor itself. Green == (+), Black == (-), right?
So I got an 18V battery, found some speaker cable and put the wires on the + and - terminals respectively....but nothing happened.

Am I doing something wrong or is the motor dead? Any input from somebody who has done this before would be greatly appreciated.
The window does not work, so I want to start by checking the motor. I have done the fuse already.

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Run hot to the black and green, reverse polarity to raise window reverse for down. Good Luck

Thanks. I found a website that had some good info for a Porsche 944, but it looks exactly the same so I followed the procedures and this is what I found:

With Ignition ON:
Red/Green wire: 12V
Blue/White wire: 12V

On motor wires --
Green (+) wire 12V without pressing switch
Black (-) wire 12V without pressing switch

There are 0 ohms when I checked resistance between the green and black wire.

Also, the cable that goes UP is as tight as a bowstring, but the cable that goes DOWN has slack. Is that normal?

With my hand on the motor, I can hear it click when I press the switch, so the motor is getting power it seems, but nothing moves up or down. Same deal when I used a 12V/18V battery.

Any ideas?

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

so, what is the problem to begin with? Maybe I missed earlier stuff...what's the problem?

The passenger window motor in my 124 recently stopped in a similar manner.
When I applied power it would click just a little, but the motor would not turn.

A new motor fixed it right up!

Tip:
There is a round plastic bumper mounted under one of the motor bolts that will fall out when you remove the motor. I spent a lot of time trying to figure out what it was and were it went.

It is a stop-limit for the regulator. If you look at the ends of the big regulator gear there is a curved "hook" on each end of the arch.
It limits against this when fully open as well as from the other side when fully closed.

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OK, here's the easiest way to see, swap the switches between the driver and passenger side and see if the drivers side power window doesn't work much better. Get it? The drivers side power window switch is used alot more than the passenger side switch yet they are the same swich, just swap em and see. It at least eliminates the motor issue....cliff

so, it looks to me as though you have ripped your whole interior apart looking for this issue? hmmmmm....well...you maybe correct ...best of luck...cliff

The window just does not work...this is the rear left side. I already swapped switches to no avail. The motors are around 120 each so I want to see if I can tell for sure it's the motor before I spend anything.

Maybe I'll to to the junkyard with a battery and try to find one that works.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

For the rear windows the entire regulator/motor assembly can be had for $140ish.....don't pay $120 for just a motor!

The passenger rear on my W124 is dead, but since I really have no need to have all 4 windows open, I'm not going to fix it. The other 3 work fine. So long as the front windows work, that's all I care about.

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Well the reason I need them working is so I can get the windows tinted. Also where can I find both for 120?

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

Try your setup on a good working motor (rear right side). Then you'll know if your diagnostic setup is valid.

Good idea. I'll give it a go.
If it does go up/down....how can I tell if the motor is good compared with the regulator?

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

If you find your diagnostic setup is valid, then you've bracketed the problem to the regulator/motor side of the connector, and you can forget about testing switches and fuses for now.

I imagine the motor would at least twitch if it was good and it was a regulator problem. Otherwise, the problem should present itself by taking the motor out, testng it, and poking around the regulator.

I am also having exactly the same issues with my right rear window. Any update from your diagnosis? Have you resolved this isssue and iif so how?

Thanks in advance

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Even if you hook up correctly, if the motor is frozen it still may not turn.

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