A drive motor for at least one wiper arm intended to wipe a glazed surface of a motor vehicle is disclosed. The motor includes a cam surface linked in concentric rotation with a rotary shaft of the drive motor, and static cam reading means able to cooperate with said cam according to the angular positions occupied by said cam to generate electrical control signals varying as a function of the angular position of the wiper arm on the glazed surface. The cam has a first circular conductive track, a second semi-circular conductive track concentric to the first conductive track and connected to same via a conductive bridge, in which the static reading means are formed by three sliding contacts able to make and break electrical contact with respectively the first and second conductive tracks and the conductive bridge depending on the angular positions occupied by said cam.