Window Regulators A window regulator, sometimes known as a window lifter or window mechanism is the mechanical apparatus inside your door that lifts the window when you press a button or in some older cars when you turn the winder. These regulators are quite a common failure in some cars, they can fail due to icing in winter or just through time. The good news is that window regulators are relatively straight forward to replace, in some cases you can replace just the mechanism and in other cases you need the full unit including the motor. Window Regulator Problems Problems with window regulators are common.