Abstract: A motor vehicle comprises a pivotal support member having at least one headlamp secured thereto, an unidirectional motor which rotates its output shaft in one rotational direction only when energized, cam and linkage means whereby rotation of the output shaft of the motor is converted into a pivotal movement of the support member about its pivot axis to adjust the headlight angles. Also provided is an electric circuit for energizing the motor which comprises a first group of electrical contacts which are connected in series with a second group of electrical contacts, respectively, a contact disc in slidable engagement with the second group of electrical contacts, and a manually operable means for selectively connecting one of the first group of electrical contacts to a battery. The contact disc is electrically connected in series with the motor and also mechanically connected to the output shaft of the motor to be rotated thereby.