The actuator (ACT) is intended to be linked to phase (AC-H) and neutral (AC-N) conductors. It comprises a motor (MOT) provided with windings (W1, W1), a capacitor (CM) disposed between two ends of the windings and the terminals of which form a first (P1) and a second (P2) phase terminal. It includes a switch (TR) controlled by an electronic unit (CPU) to link the common end of the windings to the neutral conductor, at least one pair of diodes (D1, D2; D3, D4), the diodes of one and the same pair being connected by an electrode of the same type to a resistive circuit (RA, RB, RC, DZ1, DZ2) connected to the neutral conductor, the other electrode of each diode being respectively linked to the first and second phase terminals and means (CS1, CS2) of detecting the state of conduction of the diodes.