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  #1  
Old 06-22-2016, 10:14 AM
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W123 power window intermittant failure troubleshooting

I have been having problems with my right front window. Some days it works, some days it does nothing. On days when it does nothing, I get zero motion from the window in both directions, no signs of the motor trying to turn, nothing at all. Then the next day it works fine. The only possible correlation I have noticed is that it tends to fail on hot days.

So far I have cleaned the window switch and it's contacts, tightened the terminal screws inside the door, supplied 12v directly to the motor (works fine if I do that), and cleaned and greased the regulator and window tracks.

I do have a spair motor and regulator, but hate to swap that in until I know for sure what the root cause is.

Does anyone have any suggestions? It is very difficult to troubleshoot an intermittant failure like this.

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  #2  
Old 06-22-2016, 10:45 AM
mytimeyet's Avatar
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If the left rear also does not work when the RF fails it is probably a dodgy fuse connection.
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  #3  
Old 06-22-2016, 11:01 AM
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Fuse is brand new, left rear works perfectly.
I wish it was that easy
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Old 06-22-2016, 11:33 AM
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What kind of fuse is the brand new fuse? Did you clean the fuse contacts? I had an intermittent horn for about a year, cleaned the fuse (crappy type) a few times, didn't help. Finally ordered a kit of Flosser ceramic fuses and cleaned all fuse box contacts and replaced all the fuses. No more problems with the horn or of the other circuits.
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  #5  
Old 06-22-2016, 11:35 AM
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what year is the vehicle?


if you have an '84 or '85, check the wires in the door and the rubber accordion to the door from the body.
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Old 06-22-2016, 11:39 AM
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It's an 85. I checked the wires in the door and tightened the terminal blocks. I'll check the wires inside the accordion Can I get to those from under the dash instead of pulling the door panel off, with an inspection scope for instance?

All fuses were recently replaced with brass contact new fuses. Not sure on the brand to be honest. Contacts were all cleaned with a brass wheel on a dremel and contact cleaner/deoxidizer.

Thanks for the advise!
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  #7  
Old 06-22-2016, 11:55 AM
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Quote:
Originally Posted by Demothen View Post
I have been having problems with my right front window. Some days it works, some days it does nothing. On days when it does nothing, I get zero motion from the window in both directions, no signs of the motor trying to turn, nothing at all. Then the next day it works fine. The only possible correlation I have noticed is that it tends to fail on hot days.

So far I have cleaned the window switch and it's contacts, tightened the terminal screws inside the door, supplied 12v directly to the motor (works fine if I do that), and cleaned and greased the regulator and window tracks.

I do have a spair motor and regulator, but hate to swap that in until I know for sure what the root cause is.

Does anyone have any suggestions? It is very difficult to troubleshoot an intermittant failure like this.
There are 2 window fuses, ea. fuse serves 2 windows. Does the other windo work? If so, that would sort of eliminate the fuse. Intermittent electrical failure are hard to find. I'd suggest connecting a test light bulb at the window motor and observe the behavior of the bulb. Move the bulb up the circuit towards the fuse if you determine the motor is OK.
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  #8  
Old 06-22-2016, 12:27 PM
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Quote:
Originally Posted by Demothen View Post
It's an 85. I checked the wires in the door and tightened the terminal blocks. I'll check the wires inside the accordion Can I get to those from under the dash instead of pulling the door panel off, with an inspection scope for instance?

85 is a highly likely year for this problem. been there. really aggravating.


you can pop off the accordion without doing anything else. It will go back into place without disturbing anything.
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Old 06-22-2016, 01:50 PM
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Thanks. I'll check the accordion tonight. Is there any particular reason why the '85 is more prone to problems here? Any suggestions for correcting a broken/frayed wire if I find it, besides the obvious replace the wire? Wrap it in conduit or heat shrink?
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  #10  
Old 06-22-2016, 02:06 PM
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Quote:
Originally Posted by Demothen View Post
Thanks. I'll check the accordion tonight. Is there any particular reason why the '85 is more prone to problems here? Any suggestions for correcting a broken/frayed wire if I find it, besides the obvious replace the wire? Wrap it in conduit or heat shrink?

they changed the insulation ingredients to something more earth friendly (or so Ive read) But I have witnessed it on the 85 w123 more than other w123s.

Once the accordion is off, feel the wires (I think they are wrapped in something) for knots or strange bulges. It will be pretty noticeable. If you are uncertain, cut the covering open.


I think my solution was to not 'F' around - I took off the pillar covers and door skin to replace a healthy amount of wire that was not subject to repeated bending (like in the door hinge).

solder, heatshrink should be good if its not subject to lots of movement.
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Old 06-22-2016, 02:16 PM
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Sounds like a plan. I'll probably do the same, especially if it's not difficult to get the pillar trim off to get to that end of the wire. I'd probably just splice there then run a continuous wire up to the terminal blocks in the door. I might get some fabric tape and wrap the wires with a good amount of that through the accordion area.
Thanks for the help
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  #12  
Old 06-22-2016, 02:20 PM
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smart move. now that you mention it, i added extra wrapping too, I just cant remember. Make sure you don't make that section too stiff though, that won't work in your favor.


I hope the problem is that easy. There are other suggestions that may be on the right track.


I think there is a writeup on this issue also if you do some digging.
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  #13  
Old 06-22-2016, 03:17 PM
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I read some but not all of the responses.

When I cleaned my Window switches I found I had to scrap them to the bare metal with a small pocketknife. Contact cleaner or the Pencil Erasure that some people have claimed to use would not have worked in my case.

Any burned and black medal on top of the contacts is oxidized and not going to be a good conductor of electricity.

Another possible is that the Motor Brushes are getting short (not a short circuit) in size. There is some threads on taking the Motors apart.
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  #14  
Old 06-22-2016, 03:23 PM
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Quote:
Originally Posted by Diesel911 View Post
I read some but not all of the responses.

When I cleaned my Window switches I found I had to scrap them to the bare metal with a small pocketknife. Contact cleaner or the Pencil Erasure that some people have claimed to use would not have worked in my case.

Any burned and black medal on top of the contacts is oxidized and not going to be a good conductor of electricity.

Another possible is that the Motor Brushes are getting short (not a short circuit) in size. There is some threads on taking the Motors apart.
There's actually a tool designed for cleaning electric contacts called a burnisher. The one I bought is a very thin flexible strip of metal with a slight texture to it. Unfortunately I didn't get mine until after I had cleaned the contacts - but I did use an eyeglasses screwdriver to scrape the contacts until they were completely clean.

Typically I've found that dirty contacts will fail in such a way that only the up or down action of the window is intermittent - usually the up side since that draws a bit more current I think.

I was wondering about the motor brushes being worn out. I'm going to check the wire in the rubber accordions before I pull the motors, but that's definitely something to check as well.
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  #15  
Old 06-22-2016, 03:28 PM
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Remove door panel and measure voltage drop between the 2 wires that go to the motor at the screw terminal inside the door. If you push switch and no 12 VDC there, go upstream and test right at the switch. One wire that feeds thru the rubber bellows where the door pivots had broken in my 1985.

Otherwise, the normal issues: "corroded fuse tips" (both LF & RR windows don't work) and "spilled drink on console switch" (open up switch and clean).

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