[Richard]

I don't think that removing the mirror will give you access to the solenoids. I have removed one of the mirrors by using carb cleaner to release the glue. Under the mirror are screws that hold the panel in place. But that only gives access to the cylinder and the slide adjustments for the door.

If you could use a small inspection mirror or fiberscope (good reason to buy one!) you might get a clue by following the lines out of the pneumatic door cylinder.

Another clue could be to follow the wiring out of the electrical switches for the door.

Forrest may be on to something, in that it is hidden behind a panel somewhere in the bathroom. The big question being which panel.