Yes, that's what I thought also. Since my AC and Heat are working fine and the fan is working properly for both, just how could a wire be switched? I would think that one part of the system wouldn't work at all if that were the case.

Yes, I have a humidifier connected to the furnace, but it works fine. When I turn off the humidistat, the humidifier never goes on. I believe the furnace only provides a power transformer for the humidifier. The actual switch is in my dining room next to the thermostat.

Perhaps I should unwrap the electrical tape for the wires that are above the furnace and see if some bare wires are inadvertently touching.

I like my neighbor, but I sure hope he doesn't make my problem worse!

Keep the suggestions coming....if anyone has anything else to add or ask. I really appreciate your help!