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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16875   
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It may not be the motor. If I recall correctly the motor is live all the time and the switch grounds one or other of the motor terminals. If one of the wires in the rubber conduit has broken (the usual problem) you may still read 12V on both motor terminals due to the low impedance of the motor windings.
I sugggest reading the voltage on each terminal at the same time as you press the switch, or take the reading across the terminals (which should be 0V unless you press the switch, when you should see something approximating 12V). |
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3rd Jul 2020 1:10pm |
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| nieldm Member Since: 17 Apr 2019 Location: London Posts: 6
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Thank you for the quick reply! I should have been more clear. I get 12v measuring across the terminals when I press the switch and 0 otherwise. It doesn’t look like either are permanently live though, ie either terminal to earth is 0v
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3rd Jul 2020 1:17pm |
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| Martin Site Admin Member Since: 02 Apr 2007 Location: Hook Norton Posts: 6480 
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Photo added to your post - for clarity you've got an aftermarket kit not factory.
Measuring across the feed to the motor, you should get 12V with the switch in one direction and -12V the other. If this is the case (it sounds like it is) then it's not the supply to the motor, it's the motor. You may be able to unjam/free off/service the motor, or you will have to source a replacement. Quite what that replacement would be for your aftermarket kit I don't know, sorry.  1988 90 Td5 NAS soft top
2015 D90 XS SW |
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3rd Jul 2020 1:32pm |
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| nieldm Member Since: 17 Apr 2019 Location: London Posts: 6
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Decided to strip the motor to see if there is anything obvious. It looks like the brushes are fouling on the housing and causing it to stick. Would I be correct?
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3rd Jul 2020 1:36pm |
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| Martin Site Admin Member Since: 02 Apr 2007 Location: Hook Norton Posts: 6480
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Looks like a generic universal kit, loads of the same parts on Aliexpress and here in the UK:
https://www.hawkcaralarm.com/catalog/car-v...-2-windows Shouldn't be impossible to source a motor if needed. 1988 90 Td5 NAS soft top
2015 D90 XS SW |
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3rd Jul 2020 1:37pm |
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| nieldm Member Since: 17 Apr 2019 Location: London Posts: 6
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And yep, well aware it’s aftermarket.
Can I replace it with a standard motor or do I need to change the entire mechanism? |
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3rd Jul 2020 1:38pm |
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| Martin Site Admin Member Since: 02 Apr 2007 Location: Hook Norton Posts: 6480
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Assuming the mechanism isn't at fault (perhaps detach at the winder and try it, and run the motor removed from the gearbox?) then you should be able to change the motor on its on. Get any part numbers/markings off the existing motor whilst you have it unbolted
 1988 90 Td5 NAS soft top
2015 D90 XS SW |
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3rd Jul 2020 1:40pm |
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| nieldm Member Since: 17 Apr 2019 Location: London Posts: 6
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No, the mechanism works. Even turning the motor by hand with the cover off feels “lumpy”, lots of resistance.
Now if I only had a manual winder handy I could at least do a temporary fix... |
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3rd Jul 2020 1:42pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16875
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I suspect the label on the motor is the key to the problem.
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3rd Jul 2020 2:00pm |
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