Greg here - totally new to RV - bought the 2019 Ventana 4369 used with 12K miles - everything seemed in great condition, now on my first trip. Really need some help - equipped with a Dometic control for heating. Zone 3 heats up nicely. Zones 1 and 2 blow out cold air only, regardless of my attempting every control option available. Now in Zion National Park and it is cold. Any suggestions on how to trouble shoot will be greatly appreciated. Plugged into a 50 AMP. All the best, Greg