I have no A/C and it has been really hot here. As a result, I usually drive with windows down.

This morning, my driver side window would not go down. The other three do. I seem to recall that windows were wired in diagonal pairs meaning that if driver front didn't work, the passenger rear wouldn't either.

Time to do some troubleshooting, but I thought I would ask first in case someone has had same problem and can save me some time!

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

that happened to me. Turned out to be a worn out switch

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

Thanks for input. Easy to check before taking door apart!

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Could also just be a rusty switch no longer making good contact. Time for emery cloth. On an SD the switches are in the center console and you can just hook up the good switch to the offending window for a test.

Do not know about the 300D.

They get full of dust and crud, not hard to gently take apart and POLISH the contacts ~ never, EVER sand nor abrade any electrical contact as that will cause it to fail again sooner .

Use a rubber pencil eraser or any metal polish .

Work over a light colored cloth as there are tiny balls and coil springs .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

I think Nate is right. I believe the contacts are not solid copper(?) but are just coated with copper. If you sand them off like we used to do points, you will sand off the copper coating.

You can do a proper diagnosis:

since the 3 out of 4 windows are working that tells me that the fuse and the relay is good

By looking at this diagram check if you have battery voltage at the terminal 5 of the drivers side switches with the key turned to on position.

Then with the switch out and in the UP position you should have terminal 3 going to power and terminal 4 to ground. And in the DOWN position it's 3 to ground and 4 to power.

See post number 4 in the thread. There is a picture of the wiring Terminal block at the front door (rear doors on mine don't have that).
Applying voltage to the individual wires from a battery will make it go up or down. Swapping the polarity changes the direction of the motor. The Motors are not grounded to the vehicle as a Starter Motor is.

w123 electric window issue

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84 300D, 82 Volvo 244Gl Diesel

This diagram is numbered the same as the switch on my 85 300D.



I checked the switch.
- With switch in it's normal position (centred) there is continuity between power input (3) and both terminals that lead to motor ((1) and (2). As I understand it, those voltages cancel each other so no current flows.
- When switch is pushed on the rear (UP) side, there is still continuity between (3) and (1) but not between (3) and (2).
- When pushed on front side (DOWN), the continuity is broken between (3) and (1) but not between (3) and (2)
- When UP switch is pushed, there is continuity between (2) and (4) GROUND
- When DOWN switch is pushed, there is some continuity between (1) and (4) Ground, but it varies and sometimes needle hardly moves, indicating high resistance.

So basically how this switch works, is that it switches polarity of connections to motor. At rest both sides powered when switch is actuated, one side stays connected to power and other side goes to ground. Motor runs. IOW, a reversing switch.

I have had problems with this system in past, but back then, the problems was the motor.

Next I need to see if I can open this switch!

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

I opened the switch. For anyone else finding this thread and wondering how to do it.
Slip a thin knife blade between the rocker button and the housing in the vicinity of the pivot that can be seen on outside. Do each side The rocker button can be popped out exposing the contacts below. Plan is to use pencil eraser first to clean contacts, then spray with contact cleaner. Hopefull that is all I will need to do to get switch working again. It doesn't look in bad shape.

This is a picture of mine after dis-assembling (don't lose the ball bearings!

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Yes, bet it is just rusty and will work fine after cleaning. You can use dielectric grease to hold the metal balls in place when putting back together.

That's what I was hoping for, but it still doesn't work. I checked and there is continuity through motor. I will confirm that it runs.

One thing I noticed, is that there is no socket in the wiring connector for pin 4 of the switch (ground). There is a strap under the switch from a pin at far end that must be the ground. Diagram above doesn't show that.

I need to do more checking, but it seems that the although the switch seems to work as it should, the motor is not getting a ground.

I was about to buy a new switch on Amazon.ca. Low price, but then I saw they were coming from China with delivery some time in September! May try the rock.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Confirmed that the window motor works by jumpering the wiring. Problem seems to be internal to switch. Bad internal ground connections to Left front switch, but OK for all others.

Time to move on - new switches for both sides on their way.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Wow yours looks clean inside ! .

I saved a few dead switches and used their unworn out rockers in the grubby switches I brought back to life .

The little round decals that show a window wear out, why I saved some un worn ones .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

It looks clean at first glance, but there was verdigris on the internal brass conductor plates. The ground pin didn't seem to get connected internally when operating the switch. I could probably have fixed it, but not worth the effort. Two el-cheapos on their way Actually not that cheap by the time they get here - About C$40 each. If I had been prepaired to wait a month or so, really cheap if ordered from Amaz-China

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5