Possible stuck relay in the thermostat or on the Air Handler control board. Does it stay on all the time if thermostat is set to off (not heal or cool) but fan on is set to on?
You should be able to test with a multimeter to see if the thermostat is constantly outputing 24V on "G" to eliminate stat as a possibility.
You should be able to test with a multimeter to see if the thermostat is constantly outputing 24V on "G" to eliminate stat as a possibility.
