Indoor unit is running but outdoor heat pump is not

by Timothy
(Beaufort, SC)

Lennox 12HPB60:
It's hot today! With the AC set at 79 (at 2 zones), I noticed the temperature inside climbing, but the upstairs heat exchanger fan was running. The compressor outside, however, was not running. I turned the AC off at the thermostats and the fan kept running. Then I flipped off the breakers on both the compressor and the heat exchanger, hoping to reset the system (this seemed to work one other time). When I flipped the breakers back on, even with the thermostats in the off position, the heat exchanger fan kicked on. Still no compressor, though. After a few more attempts, the fan did stay off.

Out of curiosity I asked my wife to flip the breakers on - first the compressor then the exchanger - while I stood next to the compressor. When she flipped on the compressor, nothing happened, but then she flipped on the exchanger, I heard a click in the compressor unit. Then I did it the other way. After turning them both off, I had her flip on first the exchanger (the fan came on inside). Nothing at the compressor. Then she flip on the compressor. Again I heard the click.

Electricity is flowing to the compressor/condenser unit, but it's not running. The fan free spins on top of the unit if I manually turn it (with a stick). Is this enough information to help you help me troubleshoot this beast? Thank you for your time.
Timothy