Process for determination of the position of a door, window or roof of an automobile vehicle, according to which the angular position of the rotor of the electric motor actuating this door, window or roof is determined and the position of the door, window or roof is calculated as a function of the said angular position. The position of the door, window or roof is calculated by correcting a theoretical position that depends on the angular position by a term that takes account of the stiffness of the mechanical transmission between the door, window or roof and the electric motor, this term being a function of the motor power supply current. The device embodying this process is advantageously used in an electric window winder.