Yeah, if it's righting itself it sounds like it's being told to turn off because the thermostat think it's reached the desired temperature.
You could check this easily by setting if it runs for longer by turning the thermostat up.
If it's one of the analog thermostats you can listen for a click at the thermostat when it turns on/off. If it's a digital one then check the display for current temp vs the set temp
2015 Rockwood Signature UltraLite 8281WS
2016 Ford F-250 Lariat CrewCab, 4x4, 6.2L V8