Front right, rear left power windows still not working. - PeachParts Mercedes-Benz Forum

winmutt · #1 06-17-2006, 09:01 PM

Replaced all the fuses and they are still not working. Power at the switches however. What could I be missing?

Wolfsburg · #2 06-17-2006, 09:47 PM

I have a similar problem, just the drivers window and the passenger rear don't work. Fuse blows constantly. I thought it might be a bare wire in the wire that goes thru the drivers door. Took that out and tested it and wiggled the wires, reconnected without going thru the part where the wires normally go, again all ok. Then I took all swtiches out in center consol. Well, now as soon as I touch the the swtich for the right rear window lift, the fuse blows. Same happens if I use the switch at the rear pass window. I am thinking of getting new switches for the right rear window, both center consol and at the window. Could the switch case the fuse to blow??? What a pain. I am still debating If i will look for the wiring that goes from the pass rear to the center consol. I fear this will be more difficult than the drivers wiring. Before I took it all apart I had the rear passenger working but not the drivers window and then the fuse blew too. Any ideas still form someone???
1987 300 DT

P.E.Haiges · #3 06-17-2006, 10:36 PM

Wolf,

Before I would replace the switches (they are expensive) I would remove the wires from the motor and see if the fuse still blows.

If the switch came apart inside, there could be a short that blows the fuse. The switches can be taken apart and repaired.

P E H

Fuzzball · #4 06-17-2006, 10:46 PM

I just found and fixed a direct short in the wires leading to the Passenger Rear window. The wires are inside a rubber tube, but it had worn through to the wire. Just barely making contact such that when I hit the button for that window.....POP.....fuse blown......I went through 15 fuses before I could fix that....sometimes I didn't even have to hit the button, they just blew.

It's all good now, but that was the culprit.

As for the windows that won't go down....turn on the key but don't start the car....turn on the map/dome light and press each of the window buttons. If the light dims, then you get power to the motor, it's time to start looking in the door. This is best done at night.

I have two plastic pieces to replace on the SD and one motor to replace on the D....and I'll finally be able to open all windows!!

But the SD air comes first!!

winmutt · #5 06-17-2006, 11:13 PM

My problem isnt the fuses however. I just tried them since its a new car and everyone suggested replacing all of them. I suppose I will pull the door apart tomorrow and check the curent at the motor.

Are there any other fuses that control both of these at the same time?

Wolfsburg · #6 06-17-2006, 11:36 PM

P.E. Your idea of removing the wires to the motor is a good one. I will try that as the panel is still off. I have taken the switch apart and all that one seems to be able to do is clean the contacts and the tiny ball bearing of corosion.
Fussball: Where exactly did you find your short or bare wire??? Was the wire in the door or was it under the carpeting???? I dread taking all that apart, but will do what ever it takes to fix it. I almost assume that your bare wire will be a typical spot for the wire to wear. Then I also need to fix the AC! Even in the north we had low 90's today!
Thanks for all your help!

P.E.Haiges · #7 06-18-2006, 01:45 PM

winmutt,

Not everyone suggests replacing all the fuses because I don't. Checking fuses is very easy: With something turned on (current flowing thru the fuse)in the circuit the fuse is protecting, check the voltage on both sides of the fuse.

If the voltage is the same, the fuse is OK. If the voltage is different, the fuse is open or there is resistance at one of the fuse connections.

Did U also replace the rings, bearings, water pump, radiator, valves, ETC? probably not. U don't have to replace the fuses either.

P E H

winmutt · #8 06-19-2006, 08:09 AM

So back to the original problem, is there antoher bus fuse that controls these? I have power at the switch!

P.E.Haiges · #9 06-19-2006, 08:49 AM

winmutt,

NO, only the fuse in the fuse box under the hood protects the window circuits.

Using an ohmeter, check the continuity of the wires from the switch connectors to the window motor. If there are no open circuits in the wires check for a voltage at the motor when the switch is depressed. U can tell which wires are which by noting the color code. U might try to "hotwire" the motor to see if it works. When U do this, remove all the wires from the motor. Mark which terminals the wires are connected so U can reconnect them properly.

BTW, U measured voltage at the switch, not power. Better use of terminolgy leads to better communication.

P E H

Fuzzball · #10 06-19-2006, 03:34 PM

Quote:

Originally Posted by Wolfsburg

Fussball: Where exactly did you find your short or bare wire??? Was the wire in the door or was it under the carpeting???? I dread taking all that apart, but will do what ever it takes to fix it. I almost assume that your bare wire will be a typical spot for the wire to wear. Then I also need to fix the AC! Even in the north we had low 90's today!
Thanks for all your help!

My short was where the wires come from the pillar that the door connects to, through the rubber accordian looking tube, into the door...the short was with the hole in the door.

pulled the rubber tube back and found the wires sawing over the metal every time the door was opened and closed.

put shrinkwrap around all the areas (had to cut it to do, so not a great looking job), then put lots of tape around that. haven't had any trouble since I did that.

jackcmail · #11 06-19-2006, 09:06 PM

There are also relays in the circuits for controlling the power window motors.

Wolfsburg · #12 06-19-2006, 09:16 PM

Thanks for all your help. Yes the wire was broken at the door hinge, literally broken off to 90%. Well at least it works now and thanks to all on this forum for all the help!!

flinck · #13 06-30-2006, 04:56 AM

Hi All
I noticed this threads focus on wires and fuses, so I thought I would just mention that at elast in my car (1990 300E) there is a comprehensive relay-box located under the left rear passenger seat. The plugs at this box are excellent measuring points if you're looking for open circuits or shorts in this area. Best regards

Phil · #14 06-30-2006, 10:22 AM

These pictures might help, look for this thread
Is my window motor dead or is it something else.
It won't let me attach them again since I attached them there. As you can see in the first picture there is a screw on connector block which is a good test point. I would disconnect the wires there and then try the center switch, if it still blows the fuse then its not the motor. The wires that go through at the door hing are always suspect after being bent back and forth for so many years. The switchs are easy to take apart and clean. If the fuse is ok until you press the switch then the short has to be after the switch or in the switch.