melle
South West
It'll come out in the wash.
Posts: 1,983
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Mar 22, 2021 13:49:35 GMT
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I have a BMW 1-series rear wiper motor I'm using for a little project. It has a plug with a brown, a red/ grey, and a black/ red wire. I'm guessing it's two-speed and two wires are grounds for low and high speed, so which is the positive wire? It's one of these, BMW part number 7258532, allegedly from a 2012–2017 F20/ F21 1-series:   |
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Last Edit: Apr 16, 2021 18:39:55 GMT by melle
www.saabv4.com'70 Saab 96 V4 "The Devil's Own V4" '77 Saab 95 V4 van conversion project '88 Saab 900i 8V
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Mar 22, 2021 14:45:28 GMT
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My guess would be brown is the earth & the other 2 are positives - one from the stalk & the other from a clever box that knows to sweep the rear screen when the front wipers are on & you select reverse.
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melle
South West
It'll come out in the wash.
Posts: 1,983
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Mar 22, 2021 15:23:42 GMT
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Thanks joem83 . I just connected a battery charger to it; brown is indeed negative, and if I connect red/ grey to positive it starts working. Not sure what the other wire is for, very well possible it's something clever as you suggest. When testing it I realised the motor is useless in its current form as it goes back and forth and I need one that spins 360˚. So, I'll either need to modify the "gearbox" on this one, or find a front one on eBay that just spins. The ones I've used before did just that, but they were all front ones. Never realised the rear ones were different because they directly operate the wiper... Will dig into this one first, but if that fails I'll need something with a metric shaft, ideally 8mm and approx 50-60mm long, that simply spins; I don't care what car it comes from or what mountings it has. Ideas welcome!
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Last Edit: Mar 22, 2021 15:25:45 GMT by melle
www.saabv4.com'70 Saab 96 V4 "The Devil's Own V4" '77 Saab 95 V4 van conversion project '88 Saab 900i 8V
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Rich
Club Retro Rides Member
Posts: 6,234 
Club RR Member Number: 160
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Wiper motor wiringRich
@foxmcintyre
Club Retro Rides Member 160
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Mar 22, 2021 16:18:38 GMT
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Thanks joem83 . I just connected a battery charger to it; brown is indeed negative, and if I connect red/ grey to positive it starts working. Not sure what the other wire is for, very well possible it's something clever as you suggest. When testing it I realised the motor is useless in its current form as it goes back and forth and I need one that spins 360˚. So, I'll either need to modify the "gearbox" on this one, or find a front one on eBay that just spins. The ones I've used before did just that, but they were all front ones. Never realised the rear ones were different because they directly operate the wiper... Will dig into this one first, but if that fails I'll need something with a metric shaft, ideally 8mm and approx 50-60mm long, that simply spins; I don't care what car it comes from or what mountings it has. Ideas welcome!
Mk2 golf uses a linkage even on the rear wiper so it’s a rotational motor rather than it being combined with the sweep-gearbox. |
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gryphon
Club Retro Rides Member
Posts: 330
Club RR Member Number: 157
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Wiper motor wiringgryphon
@gryphon
Club Retro Rides Member 157
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Mar 22, 2021 20:45:36 GMT
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Thanks joem83 . I just connected a battery charger to it; brown is indeed negative, and if I connect red/ grey to positive it starts working. Not sure what the other wire is for, very well possible it's something clever as you suggest. The 1 series may well have something clever going on... but if not, it could be that the R/G wire is the 'trigger' 12v feed, and the third wire is a permanent 12v feed that's used to power the motor back to the wiper parked position. That's how older motors would work - if you open them up you can generally see the contacts laid out on a rotating plate and it makes sense. |
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melle
South West
It'll come out in the wash.
Posts: 1,983
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Mar 22, 2021 21:05:17 GMT
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I'll open it up when I have time, I hope I can make it rotate by removing the contacts that trigger it to change direction (assuming there's just a worm gear and a gearwheel, and not some sort of crank mechanism in the "gearbox"). If I can get it to work that way, it's perfect for what I want it for. If not, there's plenty of choice in front wiper motors for about a tenner delivered on eBay. I couldn't find any with a long spindle, but I suppose most will have metric threads for the lock nut, which means I can extend the spindle with a coupling nut and some threaded rod.
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www.saabv4.com'70 Saab 96 V4 "The Devil's Own V4" '77 Saab 95 V4 van conversion project '88 Saab 900i 8V
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Rich
Club Retro Rides Member
Posts: 6,234
Club RR Member Number: 160
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Wiper motor wiringRich
@foxmcintyre
Club Retro Rides Member 160
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Mar 22, 2021 21:06:32 GMT
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I'll open it up when I have time, I hope I can make it rotate by removing the contacts that trigger it to change direction (assuming there's just a worm gear and a gearwheel, and not some sort of crank mechanism in the "gearbox"). 98% sure it'll have a crank arm in it and won't be easy to work-around. |
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Last Edit: Mar 22, 2021 21:07:17 GMT by Rich
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melle
South West
It'll come out in the wash.
Posts: 1,983
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Mar 22, 2021 21:30:49 GMT
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I just had a peek inside and you're right Rich, so off to eBay for a front motor. I was surprised to find JIS screws, but then noticed the gearbox is Japanese. |
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Last Edit: Mar 22, 2021 21:31:20 GMT by melle
www.saabv4.com'70 Saab 96 V4 "The Devil's Own V4" '77 Saab 95 V4 van conversion project '88 Saab 900i 8V
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melle
South West
It'll come out in the wash.
Posts: 1,983
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Apr 16, 2021 18:47:12 GMT
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I've bought a few 2012-'16 Peugeot 208 front wiper motors and they're excellent for what I want them to do. Here's a nice video on how the park function on wiper motors works, might benefit someone who also wants to release their inner Tim Hunkin (or just fix one):
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www.saabv4.com'70 Saab 96 V4 "The Devil's Own V4" '77 Saab 95 V4 van conversion project '88 Saab 900i 8V
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