Nothing is working, again. Intertherm

[pd]

Intertherm thermostat
Intertherm 901245 relay box
all the stickers are faded on the rest of the unit, but on one I can make out 3400A800 series

It's happened before that nothing worked and we come back two days later and it was working fine and continued to do so for a few years until today. Should note, we replaced the outside breaker box that feeds this home yesterday. AC wasn't needed when we turned the power back on yesterday so we didn't think/notice it wasn't working. When it warmed up today, wife noticed it wasn't working. Not on Run, Auto, Heat or Cool. Same as last time.

I removed the tstat cover and everything looks "clean". It makes the appropriate clicking sound at the appropriate temperature, but that's a mechanical thing anyway.

Where the wires join the relay, I removed all the wires and brushed away some rust that had accumulated on the relay itself. Still nothing.

Thanks for any help!