This official Norcold service bulletin describes diagnostic procedures to be used when the "recall box" High Temperature Sensor (HTS) shuts down a Norcold 1200 or 1210 fridge. Symptoms are an Li-op fault on a Norcold 1210 or simply no control panel lights on a 1200. The red light on the HTS is on in either case.
Also describes how to reset the HTS using a magnet.