ok I have a 93 mustang with electric fan, pretty new 180 thermostat and 3 bar mishimoto radiator. My heater will sometimes randomly come on after leaving it on and driving 30 plus minutes. But never reliable and it's getting colder so it's a priority. Rear defrost works great tho. My AC doesn't work either I think it may be the AC switch on passenger side engine wall cause the compressor doesn't kick on. Any help would be great. Im completely dumb in the terms of HVAC.