The fan on our air conditioner will not go off. It runs all the time in auto or on positions. This started during then night and we just left it running til we got up. My husband cut the power to the fan and the compressor, he waited 5 minutes and turned it back on. It continues to run.
There is a fan relay on the control board in the indoor unit that the contacts are probably stuck in the closed position.To check, Disconnect the green thermostat wire that comes from the thermostat to the control board and hooks to the F terminal. If the fan quits the problem is the thermostat. If it continues to run the problem is in the control board which will require a new board.