Welcome to iRV2.
Sorry you're here with problems .
Question . Is your thermostat a 4 button Duo-Therm , Comfort control unit ?
Some members report , that removing the unit from the wall and disconnecting it from power for 30 seconds performs a full reset .
First thing to try.
The actual 4 button model is no longer made and swapping it for a 5 button unit requires up dating the roof A/C control boards , but there is a company that re-builds the four button model.
EDIT : Just in case it is a four button and a reset doesn't help , info in this link might help.
http://www.irv2.com/forums/f54/duo-t...tat-75341.html