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Discussion Starter #1
Hi, firstly I hope this is the right place to put this. I have had a look and cant seem to find anything on here or on the net that is the same problem as mine.
The problem i am having is that the window wouldnt go down ..
So I took out the window motor and pressed the switch for up and it works but for going down it dont.
So I bought a second hand motor and it does the exact same thing.when i press down i hear a click from the main controls on the driver side. I have used a different switch from the rear and yet again it does the same. Goes up bit dont go down..

Has anyone experienced this or knows what it could be ??
Thanks in advance as this is driving me nuts
 

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Discussion Starter #2
So upon further inspection there is power coming for when I press up but nothing for when I press down .motor is fine
 

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sounds to me like its switch, or inbetween a micro switch thats faulty because all that happens is it changes the polarity to motor brushes to go opposite way, or is there a tooth on the cog missing? take door panel off for a look, thats all i can think of at moment, cheers
 

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Discussion Starter #4
It deffo is not the switch because I used one from the rear. What is a micro switch ? Motor is fine as I cut the wire and powered it using a power probe and it went down .only via the switch it fails to go down
 

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if thats so make sure that when you press switch make sure both sides of down switch are live ie 12volts at both sides if there is , it means there must be a break in cable from switch to motor?
 

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oh and by the way the micro or limit switch is a tiny switch that once window reaches full height it stops motor and usually gets window ready for going down, but that now usually works by the arc shaped cog behind window card.
 

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sorry to bother you again but i have read everything you have said, there MUST be a relay in circuit that changes polarity when down switch is pressed.maybe that if you can find or a small circuit board with a relay on it, thats my suggestion if it helps, when youre not there to see situation its hard to diagnose .
 

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Discussion Starter #8 (Edited)
So the cable that goes into the switch has 3 wires, middle is earth and then one is constant 5vlts (I think it was)and the other fluctuates between 1-10 but the side I'm having problems with does not go to ten.whereas all other 3 do
 

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Discussion Starter #9
oh and by the way the micro or limit switch is a tiny switch that once window reaches full height it stops motor and usually gets window ready for going down, but that now usually works by the arc shaped cog behind window card.
I've been looking online trying to find a wiring diagram to locate such relay but I have had no luck
 

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on the e39 525d drawing you have a resistor and a led but yours might not be same, tell you what i would do go to breakers and get a passengers switch, which have these items built in i presume, and try that for what it costs, because you said motor goes up and down by wiring seperately so you can rule that OUT.
 

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its connected to ecu under drivers facia apparently , but honestly i dont think you have to start delving that far, SO you put rear passenger switch on the faulty switch connections and did up and down work THEN.
 

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there is 2 relays or could be transistors? in the circuit, so when you press up one relay energises and operates motor when press down other relay kicks in and sends motor opposite way by changing polarity of motor,ie + to - and up - to + if this makes sense to you , follow wiring or find where you hear relays ,swop them over and you will find if one is faulty OR CHECK ALL EARTHS FROM SWITCH AND RELAYS,you have to find relays though or the circuit board if they are using transistors board will need changing, but try and follow what ive said , cheers john. thats as much as i know without being there.
 

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Discussion Starter #18
I have had no chance to do it today and the next three days I am away at work . I will have a look at it and see if I can trace it and find the relays. If I can I will try to upload a picture or two
 

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Discussion Starter #20
ok pal get back to you soon.
I managed to get some free time and took some pictures of the wiring and fuse box. I dont k ow if you will be able to make sense of it. (The wire that has been cut , when supplied with a live would bring the window down .otherwise nothing except for going up)
 
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