Good Morning Capt. Jay,
In order to troubleshoot this properly, I will need the model number of the unit. Does it use digital controls? If so, what are your temperature readings on the display? Please be sure that the set point is lower than room temperature for cooling
, and when you switch it over to the cool mode, that it does show a "cooling" indicator.
If all this checks out, what you can do is go to the reversing valve solenoid, and remove one of the wires from the solenoid while the unit is running. The unit running in heat, even though you have it in the cool mode, could mean a shorted relay in the logic board. If you remove the wire and the board is the problem, you will hear a very loud "swoosh". This sound is the gases inside the unit changing directions. Be careful removing the wire from the solenoid, because that is line voltage.
If you check all this, and the unit is still running in heat, then it could possible be a stuck reversing valve. Sometimes, you can free it by hitting it w/ a wrench or a hammer as suggested. If you free it, you'll also hear the swoosh. If this is the case, most likely it will stick again, and I would recommend having someone replace the valve eventually.
Feel free to email
me if you have any questions. email@example.com