Time to make that call to your service company
I have a goodman crt60-1 that cools my upstairs and the same unit for my main level.
Yesterday, I noticed the thermostat was blank, and suspected I needed to replace the battery. Upon checking, I learned the thermostat has no battery. To verify, I swtched thermostats (main level to upstairs) and found the main level thermostat was also "dead" upstairs.
If the thermostat is blank this means there is no power being fed to it from the indoor furnace. So check I checked the breaker for the furnace, and it is ok. I even reset all the breakers. Still no power.
I made sure that both doors for the furnace were secure. They were fine.
I located and inspected the 3 amp fuse on the furnace control board assuming it had blown. However, it was fine.
I know the outdoor unit has a small brown thermostat wire running into it from the inside of the home and I have disassembled the housing to make sure the wire didn't come loose or get disconnected.
The wire was fine and I have put it all back together, yet still nothing.
Any ideas will be greatly appreciated. I am stumped.
Time to make that call to your service company
Sounds like you've taken things much farther than we'd have advised you to without special training.
Time for a Pro to take over.
You must have a massive house!!
possibly a condensate float or bad condensate pump... Call a service company.
It's not rocket-science...
It's electromechanical thermodynamic engineering
I see 2 options... get out a Multimeter and use the electrical schematics on the back of the furnace panel... or 2) call a pro to do the same thing.
If you took the stat off the downstairs base and stuck it on the upstairs base,and you know the upstairs stat was good right before you took it off, and the downstairs stat didn't come back to life on the upstairs base, your stat may be DOA, with nothing wrong with the unit.
Get it checked out regardless. Something may have shorted and killed the stat. Or it's just a cheapie that died. Peace of mind will ensue if your tech elminates all causes outside of the stat itself (which in that case you may wish to invest in a higher quality thermostat...one with battery back-up).
Psychrometrics: the very foundation of HVAC. A comfort troubleshooter's best friend.