The power window switch is the electrical interface that allows the driver and passengers to control the window regulators. The driver’s side usually features a “Master Switch” cluster that controls all windows and often includes a window lock button for child safety. Internally, these switches reverse the polarity of the electricity sent to the window motor to change the direction of the glass. Because they are used frequently and exposed to rain or spilled drinks, the internal contacts often corrode, causing intermittent operation or total failure.