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How Power Windows Work

By: Karim Nice  | 

Interesting Features

  • Automatic Up/Down - The automatic-down feature is fairly common on cars with power windows. You tap and release the down switch and the window goes all the way down. This feature uses a circuit that monitors the amount of time you hold the switch down. If the switch is down for less than about half a second, the window will go all the way down until it hits the limit switch. If you hold the switch down for longer than that, the window will stop when you release the button. Automatic-up windows are less common. The problem with automatic-up windows is that if anything gets in the way of the window, such as a child, the window has to stop moving before it hurts the child. One way that carmakers control the force on the window is by designing a circuit that monitors the motor speed. If the speed slows, the circuit reverses the power to the motor so the window goes back down.
  • Window Control From Outside - On the Volkswagen in the TVcommercial, the windows can be lowered by inserting the key in the driver's door, turning and holding it. This feature is controlled by the driver's door module, which monitors a switch in the door lock. If the key is held turned for more than a set amount of time, the driver's door module lowers the windows.
  • Courtesy Power-On - Some cars maintain the power to the window circuit after you turn your car off, which saves you from having to stick your key back in the ignition if you forget to roll your window up. The power-window circuit will have a relay on the wire that provides the power. On some cars, the body controller keeps this relay closed for an extra minute or so. On other cars, it stays closed until you open a door.

For more information on power windows and related topics, check out the links below.

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Originally Published: Jan 29, 2001

Power Window FAQ

How do power windows work?
Power windows work via an electronic motor that's attached to a worm gear, which is attached to several other gears. Altogether, these parts create torque and that torque lifts the window.
Can you convert manual windows to power windows?
Manual windows can be turned into power windows, but it does require quite a bit of work. From wiring to additional in-door mechanisms, there are many components that have to be added to take windows from crank-powered to motor-powered.
How much does it cost to add power windows to a car?
To add a window regulator and motor — as well as all the other parts needed for power windows — you can expect to pay as much as $850 in parts alone.
When did cars get power windows?
Power windows were first introduced on luxury models in the 1940s.
Do power windows work when the car is off?
You do need power in order to operate power windows. Your car either needs to be running or you need to turn the car's power on (usually called "accessories" mode).

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