a strut mechanism comprising:

a strut configured to be selectively engageable with one of notches, formed on a rotatable part operably connected with a brake actuator, by being movable between an engaged position where the strut is interlocked with one of the notches formed on the rotatable part to prevent rotation of the rotatable part in one direction of releasing a brake and allow rotation of the rotatable part in an other direction of applying the brake and a disengaged position where the strut is disengaged from one of the notches of the rotatable part to allow the rotation of the rotatable part in both the directions of applying and releasing the brake, and

a strut return spring configured to exert a force moving the strut toward the disengage position; and

a parking lock actuator having a pin configured to be movable between actuated and unactuated positions, the parking lock actuator configured to lock a parking brake by actuating to move the pin from the unactuated position to the actuated position so that the pin moves the strut from the disengaged position to the engaged position and, when the strut is interlocked with one of the notches formed on the rotatable part operably connected with the brake actuator, being unactuated to return the pin from the actuated position to the unactuated position such that the strut remains in engaging with one of the notches formed on the rotatable part to prevent the rotation of the rotatable part in the one direction of releasing the brake and allow rotation of the rotatable part in the other direction of applying the brake,

wherein the parking lock actuator comprises a connector configured to electrically connect the parking lock actuator with a circuit board, wherein a heat sink is positioned between the parking lock actuator and the circuit board, and the connector of the parking lock actuator passes through the heat sink.