Hey Pete, congratulations on a beauty purchase. I cant offer any technical help personally but take a look at (
www.porsche964.co.uk)
follow technical link, to electrics, and at the bottom is an excellent article on the heating and servo repair. Loads of photos! I doesnt look to bad to fix. similar problems were described. I hope it helps.
Darren
By the way just purchased'91c2 coupe in December in Canada.