Reminds me of a almost new '98 mercedes slk (hardtop/convertible) that I was working on as the fourth person after the first three (investing 50 man hours..) couldn't get it figured out.
The fault was that the roof wouldn't fully open, it would stop half way in mid air.
The first mechanics had replaced the controller ($) and the hydraulic pump ($) and some other random parts to no avail.
It took me 15 min to see on the diagnostics computer that one of the micro switches didn't give the green light to the controller
to initiate the next step of folding (took 5 or 6 steps in total).
Looking at that micro switch showed some corrosion all seals were good so probably someone went a bit fanatic whit a pressure washer or something, after replacing the switch it all worked like a charm again.
Top tip: never assume anything, and a fresh look on the case usually helps.