Originally Posted by diver dave
Thermocouples use special extension wire and special connectors, and there are various types, and they are polarized. Type T and type K are the most likely for this temp range.
Although it is bad form to take one thermocouple and drive more than one device, it manytimes works. And sometimes, it causes noise to develop as a given display might generate a "thermocouple current pulse test" to test for an open connection.
If you use "thermistors" or Pt type sensors, different wiring rules apply.
It sounds (and looks) like the OP's sensors were NOT
thermocouples. They appear instead to be one of the many that use a proprietary "one-wire" serial data connection.
Thermocouples are different, and would require a different input on any gauge/controller.