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Old 11-15-2012, 01:50 PM
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Join Date: Oct 2012
Posts: 28
w123 Power Window (HELP!)

1980 300TD - 286xxx miles
While replacing the rear driver side window motor, my front driver side window stopped working. First thing I did was to check the fuzes - all good there - next I jumpered the sockets to confirm that the motor was functioning - all good, the motor works in both directions still when bypassing the switch. This left me to believe the switch was faulty. I checked to make sure it was clean inside and it was, looks like the switch was replaced by the PO not too long ago. Plugged it all back up and still nothing - no noise or anything. I then pulled the wiring at the door hinge to check for any cracked lines - nothing. I then tried a different switch that I know works, and nothing STILL!

I'm going crazy. I believe it is the power source from the relay or fuze, but it is just so ridiculously complex under the dash that I am not too sure where to look - it's the red wire that goes into the front driver's window switch that I suspect...any thoughts??? I've been through this and other forums exhaustively.

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Old 11-15-2012, 03:46 PM
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Location: Long Beach,CA
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The Power Window Relay shares a Fuse (#12 Fuse on mine) with some other components. But, if that was the issue none of your Power Windows wold work.

When I had My Window Switches apart I had to scrap the dark burned part off of the Switch Contacts to the bare metal.

While you do not have the Symptoms of bad Window Fuses when you check them they should be pulled out and the tips of the Fuse and where the contact inspected.

When one of my Front Windows stopped working it turned out that the Screws at the Junction/Terminal Block were both loose.

At least you know how to jumper the Windows to get them to move so you can close them.
84 300D, 82 Volvo 244Gl Diesel
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Old 11-15-2012, 03:58 PM
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Join Date: Sep 2010
Location: 2021 - The Great Florida Count-down
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If you're looking for a nice front driver's side electric window regulator, I got one FS in the FS section.
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Old 11-15-2012, 04:05 PM
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Posts: 28
ahhh...the terminal block, checking now!
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Old 11-15-2012, 04:06 PM
Silber Adler's Avatar
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Join Date: Oct 2012
Location: Living on a gravel road in a Red State
Posts: 593
Have you tried spraying some wd40 or contact cleaner into the switch?
85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.
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Old 11-15-2012, 04:17 PM
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Join Date: Apr 2010
Location: West Quebec
Posts: 4,025
It's been an awful long while but I had something like this happen on my w116.

Doesn't this occur when the lockout button on the driver's window switch isn't properly plugged in?

2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22
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Old 11-15-2012, 04:20 PM
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Location: Shelbyville, Tn
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One of the quickest ways to solve electrical issues is to replace all your fuses making sure you have the right size in each location. Very cheep way to solve many issues.

I would then pull a working switch and try that on the drivers window. New parts of any kind are well known to fail soon after installation.

Is your rear window now working ?
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

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Old 11-15-2012, 08:42 PM
Yak Yak is offline
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Location: San Antonio, TX
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Check the passenger rear window. The windows are on diagonal circuits, if the drivers front and pax rear are out, then it's possibly fuse b in the corner. Fuse 12 is the master relay, a is for one diagonal, b is for the other.
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Old 12-06-2012, 09:09 PM
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Join Date: Oct 2012
Posts: 28
Window Issue SOLVED

Well it ended up being that the switch was not grounded properly via the child safety switch. Thanks Zacharias for the tip, once I made sure the child safety switch was properly plugged in all the way the windows began working again.

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