Hello zdenka and thank you for your question. It's really not very difficult to replace the spring. First, I would recommend disconnecting the power to the unit and removing the mullion from the door. To remove the mullion, remove the two screws in the center and then lift upward on the mullion. This will free the mullion and you can now disconnect the wire harness. Now using a small screwdriver, pry the cover off the bottom hinge. This will allow you to lower the hinge and install one end of the spring in the hole and then raise the hinge, to place the other end in the top hole in the door. Replace the cover and now reinstall the mullion. I hope this will help you.