Does anyone know a shortcut to replacing a blend door on a 2001 Grand Cherokee with left/right automatic temp controls? When I remove the blend door motor, the hub on the end of the blend door shaft turns without resistance. I'm guessing the shaft is broken. How about drilling a small pilot hole and securing the hub to the shaft with a small gauge self tapping screw? Is there a timing/location issue, or does the motor turn until there is resistance?