The electrical solenoid on the "Contactor" buss will not function.
Nor will the "diverter"(?) valve to switch between heat and cool.
Does this sound like a bad circuit board?
It's getting the required 24 volts, but doesn't seem to be controlling anything.
Post the complete model and serial #. Where and how are you checking for 24 volts. Be specific. Cannot go to ground on outdoor units. Need to check to the common wire back to the indoor unit. I don't do many heat pumps but we have other Pros here that do.
"Cut it twice and it is still too short".