Rear power windows

E28 technical advice asked and given! Troubleshooting, modifications and more.
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johanswe
Posts: 21
Joined: May 14, 2017 8:33 AM
Location: Sweden

Rear power windows

Post by johanswe »

Hello! Both my power windows work infront. Both rear power windows doesent work with either the switches in front or in the rear doors. I tried to switch the switches with the ones i know work but nothing. If i put 12v from a car battery on the rear motors they work! What could be wrong?
Shawn D.
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Re: Rear power windows

Post by Shawn D. »

Is the child lock on the center console engaged? Make sure it's operating correctly and/or jump it and then see if the rear windows function.
johanswe
Posts: 21
Joined: May 14, 2017 8:33 AM
Location: Sweden

Re: Rear power windows

Post by johanswe »

I jumped it still dont work. I have 12v on the red/yellow cable in the rear door. I need to ground the multimeter on the body. Could i be missing a ground? Still dont understand why the switches not working either on the center console but the 2 front ones work.
Shawn D.
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Re: Rear power windows

Post by Shawn D. »

Sounds as if you'll have to trace the entirety of the circuits. Remember that the polarity changes based on which way the switch is pressed.

You could also try swapping the front and rear door switches.
Mike W.
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Re: Rear power windows

Post by Mike W. »

Not positive on this, but pretty sure.

The rear window switches are in a sort of series. I know if either one is removed, the window will not work with the other one. I think if one is bad it may prevent the window motor from working even if the other switch is good. What are the odds of two or more switches being bad? Well, when I got my E28 in '99 the grease on the window tracks was so stiff the rears barely worked at all. I mean barely. I took things apart, cleaned and regreased them, but if I hadn't and had continued to try to use the windows I would surely have trashed the switches due to overcurrent.

Not saying this is your problem, but you might want to remove the switches and ohm them out to check them.
johanswe
Posts: 21
Joined: May 14, 2017 8:33 AM
Location: Sweden

Re: Rear power windows

Post by johanswe »

Little update.

The power window contact in the door was heavily corroaded. Sanding them down got the motors running.

Does anyone know where i can buy new socket connector because a few broke.
Shawn D.
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Re: Rear power windows

Post by Shawn D. »

johanswe wrote: May 23, 2024 3:43 PM Does anyone know where i can buy new socket connector because a few broke.
I don't believe they are available new. You're going to need to splice in a used set of connectors.
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