I can only find tips for the front, nothing about the rear one.
https://www.youtube.com/watch?v=j3xCFajImBc
---------- Post added at 16:12 ---------- Previous post was at 16:04 ----------
Have you tried turning on the rear wiper, then switching off the ignition when it the blade is at the top of it's arc? There might be a lock involved when the arm is at its rest position.