The unit cools but will not heat. The reversing value is picked for cooling , but when we go to heating it stays in cool mode. I have replaced all the controls boards and it still will on heat and the reversing value says picked for cooling. You disconnect power to the value then it heat up. On the defrost board what is the setting on that pin. its set to 3 to 4. Would this have anyting to do with it? Thank you.