What is a window regulator?
A window regulator or window winder (depending on its operation) is used to roll down and push up the side windows. It is located inside your door.
Window regulators consist of metal rails, pulleys and wires. If electric, a window regulator is also equipped with a small electric motor. There are two different kinds of window regulators: with and without comfort function. If you have a car with comfort function you will only need to push the once for the window to roll down completely.