I have a Trane air handler and heater my thermostat just quit working (honeywell digital) no power nothing what's some things I can check. I replaced the thermostat with a new one and nothing happened.

Thanks

See this thread for some suggestions...
https://www.askmehelpdesk.com/heating-air-conditioning/programmable-thermostat-went-blank-32852.html?highlight=battery+free

If you have a volt meter you can check the voltage. If not, and it is 24 volt you can jumper R-G and the fan should run.R-y and A/C should run. If they do not This is an indication that you have no power to the stat.