I have no power to the Debonair 220 thermostat (heating and air), no light. As result we cannot put on the heater. Where does it get it's power? Do I need to crawl in the Attic to start tracing the wires. Eventually, the wires come down into the furnace.

Dan

If you Google the manual for your unit you will see it is 24VAC . Therefore, make sure you have power to the control board, look for a bad fuse, and you should measure 24VAC across the R and C terminals on the thermostat. You may have a bad transformer but you will need to do a little troubleshooting. Here is the manual
https://quobensspokle.files.wordpres...bonair-220.pdf