I have read a lot of posts about power windows problems. I'll add mine to the mix. The left side windows (both driver's and passenger's) don't work in my 84 300 SD. No sound of motor turning or anything. The fuses are fine and I swapped left and right hand switches to show that both switches seem to be functioning. I removed the panel on the driver's side door and measured the voltage across the motor terminals. The voltage across them ALWAYS seems to be around 12.3 volts. It drops about 0.1 volt only (to 12.2 v) when the switch is moved to the down position, but the 'up' position and the central position result in about the same voltage across the motor.

I'd guess it to be the motor that's the problem, but the consistency of the voltages doesn't make sense to me at all. Shouldn't it swap polarity when I switch from 'up' to 'down?'

Is the regulator (not motor) rusted/stuck? Mine was on the RF.

Think you have problems... my LR window only works when the door is open. When it's closed, motor operation is a negative. Wires aren't cut or out of the covering, I believe I have a bad solder point in the wire to the switch.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

The passenger front window on our '83 is "stuck" it doesn't move but pressing the switch will slightly dim the dome light, so we believe it may just be stuck....or it has a bad motor....

Stealership managed to break the window regulator on the driver rear window when it was brought in for the vacuum issue a few days ago....how did this happen? The guy who went out to test it (joyriding) had to put allll the windows allll the way down, and managed to snap the plastic tab that connects the regulator/motor arm to the window/glass slider.....so now they are going to fix/replace it for free this week See, going to the stealer can result in lots of freebies as long as they break something

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

on my new to me 80 300sdi have three windows jammed, seems the main aluminum chassis for the linkage has warped bad in the passanger rear with two screws missing, similar warping in the front passanger combined with binding and a stripped nylon worm gear on the motor. rear drivers? it seems bosch upgraded these motors over the years but they are a pricy number. i would check that your linkage is lubed, screwed down and straight. anybody know what the best linkage lube would be? i used spray silicone. and anyone have a good window motor parts lead? since i am los angelsmog i am going to the auto recycler and pulling some doors apart next day off. i checked power on mine and i guessed the switch opened a ground. binding and loss of lubricity seems to be an issue with any old vehicle window.

i would think white lithium would be good for the sliding parts or wheel bearing grease. i would use some silicone spray on the rubber parts. the above post with the motors reacting to current may just be stuck. disassembling them and cleaning everything will sometimes work, especially on a car that has sat.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I've struggled with the RR window on the SD for over one year (not very high on "the list"). I've completely checked this system, and installed a different, brand new switch, and the window has failed to operate from the driver's console. The fuse blows instantly. It appears that the switch is slightly different than the original one in the vehicle. When I substitute the LR (factory) switch, everything is fine.

Well, onto your issue.

First, rule out the motor. Get a 12V source and a good ground. Apply these to the motor leads. See if you can get the window to move up and down with all switches and fuses removed from the test. If the window won't move in one direction, reverse the leads and see if it will move in the opposite direction.

Once you do this, repost with the results and then we can know where to go from here.

I've got a complete test diagram somewhere with all the voltages at the various pins and what each one should be doing.

Another thing to check is if you're getting 12v to the door/motor at all.

The TD had a rear window that would not work. I traced the wiring from the console switches to the door window switch, somewhere in there it lost continuity. The harness at the hinge "looked" fine, I opened the wiring harness all the way from the switch console to the B-pillar and had power, but nothing as it entered the door.

Finally tore out the harness from the door and found three wires that were smashed through by opening and closing the door? This is INSIDE the rubber boot AND in the stock harness cover that looked un-touched. It looks like it had never been apart and the owner says it never did work and no dealer could find it.

That took me a few hours to find. None of the usual suspects.

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1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

I agree with TomJ. I had to splice a new wire into the harness on my daughters car for the rear right door. After years of flexing the wire can break in the door hinge area. So check the wire continuity of the harness also.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

I've been doing other things on my other car and finally got back to my Mercedes ('84 300 SD) and to the window issue. Thank you all for your replies. Here is where I am at now:

BOTH wires on the motor seem to be at about 12 V relative to ground when the switch is in neutral position When the switch is moved to the 'up' or 'down' position, the voltage seems to vary by about 0.3 V, that's it... But its the same on both leads.

So, I finally managed to pull out the window motor. Now my window moves up and down (by hand) with ease. The motor itself has a resistance across its terminals of about 1.3 ohms. It is impossible to turn by hand, but does turn with a wrench or pliers. When I put 12 V (car battery) across it I hear a spark, but it doesn't seem to turn at all. Is it possible to open it up (I don't see an obvious way) and see if the windings are intact?

So, my problem seems to be at least with the motor, and maybe also with the wiring.....

I've pulled them apart before, the motor casing has to have the ears pried off.

Remember, it's geared, so it's going to be hard to turn by hand, but you should be able to put 12v accross it and get it to run. Try a battery charger for a source, that way you can see how many amps it's drawing.

LMK if it's hosed, I have a number of assy's with bent-up regulators but good motors.

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1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

Tomj, how did you fix those wires? RR door on 84 300D has the same problem. Sometimes I can get it to work by swinging the door back and forth. But sometimes I have to take the panel off and really jiggle the wiring harness while holding the switch on. I think my problem is also inside the rubber boot. What is the best way to fix this? I don't want to re-wire the entire harness but I do want to put my "fix" in a place that doesn't have to bend. Am I being clear? Thanks for any info. you can add.

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Bruce

73 220D (never left Germany)
81 300D (totaled)
84 300D (Purchased '03, sold '17)
85 300SD (purchased 10/01/03)

I cut the wires inside the door, pulled them through from the 'B' pillar and soldered in new (long) wires that were one gauge heavier, then fed them back through the frame/door and re-soldered inside the door. Not the fastest way, but the most permanently effective.

Use heat shrink on conns and wrap the harness back up with friction tape.

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1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

Back again. My driver's window motor is toasted from what I can tell. After removing it I hooked it up to 12 V high-current power supply and the voltage dropped to 1 volt and nothing happened as far as motion is concerned. So, tomj, I'd be interested in talking to you about a brose motor, which is the type I pulled out.

Interestingly, I pulled put the door trim on the driver's passenger side. That motor is fine, though. 2 lantern batteries in series allowed it to go up and down, so that one's a wiring issue.

Tom, I am away through July 5. I'll contact you after I am back to find out how much you'd want for the brose window motor (or you can post a reply or send me a private message, as you wish).

Thanks.

Dan, 84 300SD 203 K