Power windows have been extant since the 1950s.
To fix a power window, you have to know how it's put together and whether it has a relay. Power window relays allow window operation when the car is turned off and may complicate the repair process.
Electromagnets
Electromagnets are only magnetic while charged. In a power window relay, the electromagnet is an iron core wrapped in coiled wire. Electricity is fed into the magnet, creating a magnetic field that lasts as long as its charge.
How Relays Work
Relays get their electricity from the battery. The resulting magnetic field pushes a switch into place. This switch connects the power window to the car battery for as long as the electromagnet stays charged.
What Power Window Relays Do
Since the relay can retain electricity in its electromagnet, it can keep the window and battery connected even after the car is turned off. The charge only lasts a short time, but long enough to roll the windows up after removing the keys from the ignition.
Tags: magnetic field, What Power, What Power Window, window battery