I am trying to fix a window problem in my 1985 300D Turbo. The front left and right rear do not operate. I have determined that the window motors do work, the fuse is good, I get 12+ volts at the window motor connection inside the door with the key on and not using the switch on both the green and black wires. I cleaned the switch.

I hope that the following is not related but in the last three months I have lost the use of my A/C (believe it is the compressor), shortly after that my tachometer did not work and then the clock stopped.

Any thought or ideas would be appreciated.

Thanks

DD

Everything checked out. Power at both side of the fuse. Then I read, forget the fuse, just replace it. What, why replace a fuse that checks good. They also recommended getting rid of the aluminum fuse. So I simply replaced that fuse with a red copper laced fuse, and fixed the problem. Try it, you'll like it!

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

Mercedes fused the system diagonally so that you would always be able to open one front window and one rear, one left and one right, even if the others wouldn't work. That said, it also makes diagnosis easier, because a diagonal failure points to the fuse or associated hardware: connectors, wiring between the fuse panel and the console, etc.

It's almost impossible to see the slight corrosion that will keep a fuse from conducting the kind of current that the window motor requires. Even a few electrons sneaking through the aluminum oxide will be sufficient to get a reading out of your voltmeter but no way will the window motor work.

That's also part of the advantage of using copper fuses instead of aluminum: copper corrosion can be seen more easily than aluminum oxide. It is also possible to lightly sandpaper the fuse ends and restore their ability to conduct. Not really worth doing if you have new fuses but a good band-aid to remember if you're stranded away from home.

I suspect that the fuse style we use may be getting harder to find. Most cars don't use that kind any more, right? Best to carry some spares.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

You can also source a "buss" style fuse, it's series GBC for replacement fuses. Looks like the older style cylindrical glass fuse, except the ends are pointed. The GBC nomeclature gives you the correct length and end style. I've been using these for decades and have not had any issues.

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

I'll try new fuses

thanks!

Did you know deisel is spelled diesel, but maybe you like it that way.

__________________
Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

I tried it I liked it, and most importantly it worked. I had read on this site that before I post an electrical question I should change the fuses. They looked good and fresh. Sorry.

Thanks for the help.

P.S.

For some reason wanted to spell it that way but I can't remember now what that reason was so now I'm stuck with it. At least I got Denver right. (go rockies)