Norcold N8x circa 1918-19. Works fine in cooler weather, but get 90+ and interior temps start to rise above 50+. Jayco dealership says they can find nothing wrong. RV lives in TX and this is the third time in 10 months it has been a problem. I am guessing they have RV inside a work bay with some air circulation - unlike conditions at a RV park in full sun. They just turned it on and checked the interior temp for 1-1/2 days. Said temp in frig was 33-34. Brought home, interior temps 60+. They have not mentioned anything about thermister resistance, adding a cooling fan, checking roof vent for proper ventilation, etc. Should they not be checking these items? At what point do I yell "Uncle" and demand a replacement?