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1984 Mercedes-Benz 300SD Turbo; 1985 300CD Turbo
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163 Posts
Discussion Starter #1
Hey gang,

Well a few months my passenger side front window just completely stopped working. If you push the button you hear no sound and the window doesn't move at. It doesn't seem like the window regulator is even being communicated to. Also, around this time, I kept blowing a fuse for all the windows. That has since stopped. I should also note that the rear window button works perfectly and that window goes up and down without hesitation.

I believe the problem is more than likely electrical; however, I have NO IDEA to where to begin.

Any suggestions?
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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10,152 Posts
Make sure there is not a pinched wire between the door and jamb.

Carefully clean the switch too.
 

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1984 300sd turbo
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18 Posts
My first guess is that your motor in the door has shorted out. That would explain why
the fuse was blowing. Repeated attempts to replace the fuse has caused the wiring
in the motor to finally blow. That's why you don't hear the motor trying to work.

You are going to have to open up the door and check to see if the motor gets power
when you try opening or closing the window. If there is power to the motor, and the
fuse is good, then the motor is shot.

I don't have an electrical schematic with me now, but I guess if you aren't getting
power to the motor it could be something between the fuse block and the motor.

Will
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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10,152 Posts
As mentioned you'll need to remove the inner door panel to gain access.

Blown fuses, also as mentioned, indicate a short of some kind.

Maybe bare wires touching the frame, or an electric motor with very short brushes. This will put a higher than normal load on the motor, blowing the fuse.

Apply 12 volts to the leads on the motor.

Video soon.
 

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1984 Mercedes-Benz 300SD Turbo; 1985 300CD Turbo
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163 Posts
Discussion Starter #9
Ok, so it is definitely NOT the switch.

Could I use another car battery to test the window regulator if I don't have a battery pack? Or is that terribly dangerous?

Let me know.
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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10,152 Posts
Yes, you can use jumper cables attached to a nail even. Just be careful and don't touch them together.

That battery pack I used is nothing but a battery inside with a cigar lighter socket, an air pump and the, too short for comfort, leads.

I also have a 12 volt power supply I bought at Radio Shack, but it is only 3 amps, I didn't try it, perhaps would have worked.
 

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'82 Euro 500SEL, '85 Euro 500SEC AMG WB Cabriolet,'86 Euro 500SEC RUF
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9,487 Posts
I made a pair of test cables from #14(IIRC) about 10 ft. long with alligator clips, one red (power), one black (ground). I clip to the car's battery posts and use to test the window motor at the junction of the two wires in the door. I remove the switch wires the ground one motor wire and touch the red wire to the other motor wire. If motor is good it will move one way or the other. simply switch ground and power to move the other way. you may find that the actuator assy is bound or in a "dead" spot.
 

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from small to large
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885 Posts
although op said the switch is NOT the issue, i have seen more of cases the culprit was right there. after ruling out other causes, take the switch out, open up and clean it thoroughly. you will see the difference.
 
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