Motor will now shut off...yesss! I could not believe switch was defective, it is too simple, nothing to go wrong, so.... built a little jumper and ran it from the switch terminal that 'stayed hot' to the wire that was supposed to be there. When the motor would not shut off (after reaching top temperature) I disconnected the jumper I made, the switch terminal shut down but the wire from/to it, remained hot.....so back under the hood with the tester and discovered that power was being fed back to the switch from an electronic/electric choke that had been installed before I got the car. My guess is that a diode built into it failed when the heat built up and it was not operating properly. Pulled the choke wiring and sensor out and everything is fine. File that away in your memory banks.