How did you test the thermistor? It won't measure like a fuse or thermostat. A good thermistor will read approx 12,000 ohms at room temp when measured with an ohm meter. The resistance changes with temperature. The sensor strips are simply 2 strips of metal. Unless one is physically broken, it's ok. Again, I think you should put the dryer back together, wash a load of clothes and try drying them before you start looking for trouble.