I disassembled the fan a couple of days ago.
I think there is no chance to get it from the outside. IŽll creep under my car in a few minutes looking for a way to disassemble it from the bottom, but I got it from inside. You need to disassemble some dashboard parts, i.e. the glove compartment. (As I totally demounted the interior I didnŽt mind to take out the heating regulators, radio and check control, too, but it should work without). The fan is a black plastic part behind the glove compartment. ItŽs connected with the heating. I warn you from detaching the heating. ItŽs attached to the motorŽs cooling system, the coolant will mess up your interior.
To demount the glove compartment you firstly have to open it, detach the bottom part and then detach some screws in the top. The glove compartment is connected to the middle part of the dashboard by two screws tricky to reach. They are cross screws turned from the inside of the board. YouŽll have to touch for them. Maybe youŽll see them when you creep under the glove compartment. IŽll upload a picture if you want me to.
Once the glove compartment is removed, the fan should be easily detacheable. Look for screws and maybe be a little brutal. :-)
Sorry for my little English, but I tried to describe it as well as possible.
If you have a cheap opportunity to call me in Germany IŽll try to explain it more detailed.
Ask me per E-Mail or PM if you have any trouble.