The read out on my White Rogers Digital 1F86-344 series 80 thermostat has turned black on green temperature read out screen. Furnace is working. Batteries are new and installed correctly. Any ideas or solutions would be appreciated. Thermostat is about three years old. I can always replace thermostat but would like any ideas why his would happen.

Look through the setup screens, it may have a settings point.

I suspect a component on the circuit board has burned out. I suggest replacing the stat.