Generally
A newly manufactured hydraulic tube in original design for the front seat. 1 Hydraultub is required for 1 car.
It works like this:
If you press the button so that the seat moves in one direction, the electric hydraulic pump in the engine room starts. At the same time, current is sent to the hydraulic tube's solenoid, which opens a small valve at the bottom of the tube. The entire hydraulic system is pressurized and there is only one place that is open, the valve to the tube that sits under the front seat. The hydraulic tube pushes the seat which moves, release the button when the seat is in the end position.
If you now want the seat to move in the other direction. Press the button in the other direction and current is sent to the hydraulic tube's solenoid which opens the small valve at the bottom of the tube. The pump does not start, but the strong return spring in the seat mechanism retracts the tube piston rod and seat, the oil is forced out of the hydraulic tube and back into the reservoir under the pump. Release the button when the seat is in the end position.