2018 Santa Fe heater always overshoots so you are getting blasted with too hot or too cold air as it tries to achieve the preset temp. Even when switched to manual mode there is no instant response to changing the setting. Service mgr. wants it in overnight so it can be monitored but I thought someone could explain if this is a software problem. Don't want to drop car half hour away at dealer, have it run all night only to hear they think there's no problem. Only had it 10 months.