I figured you had either a bad AC relay or a combined bad thermo switch and a bad cooling fan relay.
With your troubleshooting so-far I'll bet you had the latter. It looks like the cooling fan relay is still stuck in the closed (energized) position. Pull the relay and and use an ohm meter to see which pins are closed. De energized, it looks like pins 30 and 87 should have infinite resistance. Same with pins A and B. If either or both sets have close to zero resistance while deenergized, then the relay is bad.
Or lightly yet firmly tap on it a few times, reinstall, and see if that fixed it.
http://www.pelicanparts.com/944/electrical/944_84_AC_2.jpg
This is a swag because I'm looking at the schematics for an '84 944, but the wiring logic seems to be the same. I believe the relay is the same in early and late models (Part # 141-951-253B which is about $8 from Pelican Parts).