Host reads second nozzle at constant, incorrect temperature.
When attempting to use a second extruder, the second extruder displays a constant temperature of 100°C. Temperature can be adjusted manually from the board itself, but Repetier Host always displays a temp of 100.
Comments
What firmware are you using and what is the M105 response? You can enable logging in host (Preferences->basic) and in any case you see the answer there.
For example, when heater 1 is set to 40C and heater 2 is disconnected: the return is
But the control panel still displays heater 2 as being at 100C.
I'm using Marlin 1.1.6