Abstract: A hydraulic actuating device for a convertible top assembly of a motor vehicle. The actuating device comprises a hydraulic pump with an associated electric pump motor and one or more hydraulic actuators, each for driving an associated movable part of the convertible top assembly. The actuating device also comprises a control circuit for effecting a defined sequence of movements of the one or more actuators and feedback means, which are connected to the control unit, for feeding information relating to the sequence of movements of an actuator back to the control unit. The feedback means comprise means for measuring the electric power consumed by the pump motor, which means transmit a feedback signal to the control unit.