In Heat mode, compressor outside continues to run even when the blower inside is not running. If I switch the thermostat switch from Heat to off, the compressor stops but sometimes kicks back on, even with the thermostat switch still in the off position. At this point, I have to cut power via the breaker to stop the compressor. I'm assuming this is a control board problem, but don't know the troubleshoot steps.

Thanks,

Brent

I would check the starter /contactor for the compressor. It is also possible that one of the 24 volt low voltage wires from the thermostat to the air handler or air handler to the outside unit has shouted out causing this intermittent problem.

If you have a dog that is outside the wires could have been chewed on also.