How do Power Windows know when to Stop

[Nitrate]

1981. 2000. Is there some kind of circuitry that stops the motor when it's all the way up and all the way down? Rich B.

[ORFORD2004]

You have a 90 degrees piece of metal with the screw that hold the window for the up position. Nothing for down since the window will stop at the bottom.

[aevansgatech]

As far as circuitry/switch goes, I don't believe so. My switches stay up until I return them to the center position.

[Nitrate]

So the motor is still trying to push the window up and it's only you returning the switch to the center position that stops the motor? My power antenna motor stops automatically when it reaches its full extension. I don't have to switch the motor off. I thought the power windows worked the same way. No? Rich B.

[DieselSpider]

Some of the systems had a current gate that read a spike in power draw and cut out the current to the motor when the window hit the end of its travel and prevented the motor from spinning since when the motor jams and can't spin there is a big spike in current draw. If the circuit does not have a power board with a power regulator chip on it a then its the user that turns the motor off before it burns out. Many times this will be all encapsulated in a block of epoxy.

If the window motor comes on for a moment when its already all the way up and immediately turns off when you turn the switch to the up position again then it has the current gate on it however if the motor just keeps humming and such until you return the switch to its centered position then it likely does not. You can test this with a voltage meter at the motor and see if the power turns off automatically a moment after the window reaches the limit of its travel. You may even see a momentary voltage drop just before the gate turns off the power.

Also if you put the windows up without the engine running the courtesy light will usually clue you in by dimming for a moment and then getting brighter when the window reaches the end of travel if it automatically cuts power at that time however if it just goes dim and stays that way until you return the switch to the center position then the window motor is not protected by any automated cut our circuitry.

You have a few ways of checking depending far you want to dig into it.

[Nitrate]

Diesel, Thank you for a through rundown on the operation of power windows. Very helpfull. I would have been hours maybe days searching the web for just that information. Appreciate you taking the time. Rich B.

[DieselSpider]

Powered steps on an RV use a similar module tied to the magnet switch on the door. Saves a bit of extra wiring and adjusting of stop sensors.

[Redline]

"How do power windows know when to stop?"

In the case of the 124, I thought the answer was always "When they're reached halfway up".

[GTO]

Found the following link on google for wiring diagram for 2000 spyder:

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http://storage.fiat-bg.org/Books/Fiat124Spider/1980%20Wiring%20Diagrams.pdf

Hope it helps.