Blower is always on at low speed in my 90 and that the way it is supposed to be
That little fan you have is shot, there is a thread on Rennlist about adapting a Jaguar climate control motor as the Porsche?Denso is about $300
Very common problem with those
I am sure ToreB will have the answer to the closet circuit...whatever that is in fact you can learn alot about the CCU by going to his site
http://www.bergvillfx.com/porschehvac2.html
Nostrovia..