On Monday, June 4, 2018 at 6:34:51 PM UTC-4, Scott Frederick wrote:
Thanks for the information. It's been 26 hours of functioning correctly.
It's a Goodman GPH1336H41AC all-in-one heatpump package unit for a cabin.
No condenser fan or compressor operation when acting up. Just the air handler fan.
Seems to be one of three things: thermostat, contacter, or transformer.
So I got my multimeter and I'm waiting for it to fail again.

I think you can probably rule out the thermostat. The thermostat only
calls for cooling, the air handler is turned on by the controller board.
The thermostat can turn the air handler on separately, if you want fan
only, but in cooling mode it's turned on by the system. So, if the air
handler is running, I'd check to see if the contactor has 240V on either
side and if it has it's 24V turn on voltage.