Sprintgtc, yes, I found your diagram, so I knew the 2-wire switch wouldn't work. Thank you for posting it! Once I get all the parts rounded up, it will be a big help. We have the relay but no switch.
Searching the posts on the bb, I've seen pictures of the dealer-installed switches and they look very much like the fan, dash light, and wiper switches. In fact, the wiper switch is a 4-wire. I wonder if it would work. . . I don't know a whole lot about electrical, I would say yes, but does anyone more knowledgeable know?
https://www.centerlinealfa.com/store/1968
Thanks!