Dometic interior heater turning on and off constantly

Yes once it reached a set temp it will short cycle after a few minutes also it does not change anything weather or not its on shore power or not and there are no vents blowing on it. Forgot to mention it but I set the temp differential to 1 degree and that changed nothing to. Like I mentioned before if I crank the temp up real high the heater will run great getting up to that temp, it just likes to short cycle after it gets there.