Ditto+ Probelm

We have a problem. The ditto+ is reading a heat of around 354 C which means that the printer will not heat up because it thinks that to get the the appropriate temperature it needs to cool down. So when we tell it to print something will will just sit there and try to cool down to temperature it cannot cool down to because its temperature is not higher than the temperature we want it at. We think that the issue is with the thermistor because we have checked the wiring for loose connections. If you have any ideas about how to fix this it would be appreciated.