I am having trouble with a 10 year old Amana PTAC unit. It will not control temperature when in the AC mode. It will freeze you out of the room, but won't control. Recently I purchased an external thermostat (Totaline/Venstar T1010), the required wiring harness kit from Amana (PWHK01C) and some thermostat wire. All connections were made per direction from Amana and Totaline. The thermostat works, with one caveat. The reversing valve cycles when no system call (heat or air) is in progress. As soon as the thermostat calls for heat or air the unit works great. As soon as the temperature reaches the setpoint and the unit stops, the reversing valve begins to cycle again. As the name implies, I'm 'outa my league' here. Any thoughts?