Good morning. I'm a mid level do it yourselfer. I have a split system heating/AC system with two units. System 1 is working fine and blowing hot. System 2 is not blowing on either heat or air. I swapped the thermostats and had similar results, so it's not the thermostat. I also checked the breaker box and system 2 was not tripped. Any suggestion on where to go next? Thanks

Get your multitester out and try the relay switch or the capacitor and see which one is kaput. A/C and heating is not that complicated to figure out. I would think you also need to check out the blower motor as well while you are at it.