Closing your power window is as easy as pressing or pulling on the window switch until your window reaches the top. It only takes a few seconds to close the window, but those few seconds take the driver’s concentration away from the road. It is becoming increasingly common for power windows to have an express-up function so the driver can press the power window button and the rest of the process is automatic.

The danger of the power window express-up feature is if there is an obstruction preventing the window from closing all the way. It can cause damage whether that obstruction is:

  • A child’s arm, head or toy
  • A chunk of ice or snow
  • A piece of dirt or a stone stuck in the window track

When the window reaches the obstruction, it can cause bodily harm or the window can shatter if the obstruction is hard. To add a safety device to the express-up feature, car makers use an anti-pinch device. The window motor has a pressure sensor that detects window motor movement when the glass has stopped moving, even minutely. If this occurs, the window reverses direction and moves downward.

The anti-pinch feature is controlled by a small module which is now often integrated into the power window switches on the driver’s door. If the vehicle loses battery power or the power windows require a repair, the power windows will not know their upper and lower limits. The window motor will need to be re-trained so it can learn the window travel limits.

This article originally appeared on YourMechanic.com as How Does the Power Windows Anti-Pinch Safety Feature Work? and was authored by Jason Unrau.


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