The heater won't flip to blow on the floor---it works in every other position!
('05 dodge)

 

When Dodge got rid of the vacuum pumps they went to little electric motors to change the havac systems doors. You might have a bad one or the linkage could have dropped off.

Someone who has a service manual may be able to tell you how many and which one affects your problem.

Dave

 

Sounds like you may have a blend door issue. It may be broken not allowing it to adjust correctly.

 

Read this thread for general info.

https://www.dieseltruckresource.com/....html?t=210483