When I try to get heat to the "lower" vents, the defroster stays on and the majority of the warm air goes out there. There is also a control for a lower/defroster split. There is no difference in the air flow using either control. Most of the air goes out the defroster while my feet freeze. The service tech at the dealership told me that Dodge told him that that is how it works. Everyone at the dealership agreed that it makes no sense to have two control buttons have the same function, and the fact that the system did not work like this last winter did not seem to matter. The dealership told me that they can only do what Dodge tells them they can do. From the little amount of research I have done, I have discovered that this is a very common problem with Dodge, especially with the Rams, but it is a very expensive fix.