I have two Honeywell T8601 thermostats in the house, one upstairs and one downstairs. The floors both have separate blower and a/c units. Last night I pressed the info button on the upstairs thermostat and the display went blank. I checked the fuse box and nothing has been thrown. I swapped out the downstairs thermostat with the one from upstairs and it displayed fine. The therm. taken from downstairs would not display upstairs. So, it's not an issue with the thermostat itself.
Any thoughts on if the cause could be in the components on the mounting plate or at the a/c unit or blower? If so, any suggestions on how to isolate the problem?
Thanks in advance.