you have a digital heater control yes...the problem is in there,
i had a similar thing with it turning itself on and off randomly and the AC going even when switched off . dont replace the unit it'll cost you plenty
its a capacitor fault (like a 3c fix)
i got a mate to solder in a new cap and all problems fixed - guess thats why the wrecker wanted like $200 with exchange of broken unit - the bastards!!