I installed one from scratch, and it used a front motor with a pulley/cable system to pull the glass back over the roof. However, with a factory installed unit, i have no idea. I always dreaded my sunroof breaking because it looks like a lot of work. Good luck wish I could give you better pointers..
Ok so this is still a problem any ideas people. Haven't had time or ambition lately to tear it out blindly or to find shop manuals. But with climate control problems it would be nice to open it up without fear of it being stuck.
A couple of years ago my sunroof was stuck. finally i got sick of it. I could hear the motor trying to move but the glass was stuck. As I held the button down, I pushed on the glass and it broke free. haven't had a problem with it since. (Yes I was prepared to go a repair shop if it stopped again while open. And I made sure there was no rain in the forecast).