I am not an authority on your car, but I do know a little about electricity. Try and test the resistances in the blower motor. Maybe its trying to draw too much voltage/amps through the resistor. Just my wild guess. Good luck!
1964.5 convertible and a 2012 Sterling Grey GT. 100 hp. and 412 hp. Go Bama, Roll Tide! 2015 National Champions! Clemson put up one heck of a fight!