Maybe I made better cable reconnects when I reassembled the Mini yesterday. Internal sound is working again, too.
From my travels I've found that an open/bad connection on a temp sensor will cause the machine to think that the temp has risen though. It's a failsafe mechanism that I've seen on all kinds of equipment in case of a bad sensor or open connection so that your unit doesn't overheat.
If it was a bad thermal sensor connection it would cause the fans to ramp up right away.
BTW I mentioned resetting the SMC as fan speed control is one of its functions.