You should be able to find some docs on how to dismantle the A/C, vents etc here:
Most probably it's available on the internet temporarily only
The diagrams don't open, as they are scalable vector graphics, but apparently from what
@NavNie wrote
here, it can be saved as html and then opened offline with a browser. If that won't work, earlier in the same thread I've wrote my way of dealing with the problem.
That's what I'm also thinking about. There could be something that has not been reassembled properly and water gets into the A/C and ventilation system.
Is the windscreen original? There is coded production date (2 digits of the year + up to 12 dots showing month).