A question is if you lower the temp way down will it shut off. So if you know the temp of the MH interior is 70* and you put the thermostat on 60* then will it shut down? If not then gouble check the thermostat setting for the FAN. If it is in AUTO then the unit will shut down the fan when the heat pump shuts after the set temp is reached. If in LOW, HIGH setting then the FAN will stay running but the compressor for the heat pump will shut off making it seem to run all the time.
Does your thermostat have a remote temp probe under a little plastic dome away from the thermostat?
"Gunner" USN Retired, Airdale
2004 Monaco Signature 44' Conquest. Detroit 60