I was just on my way through the rocky mountains and it started to get really cold in the cab, I could hear the blower motor still working and felt the vents and I could feel really warm air but no flow out of the vents... So that pretty much rules out the blower motor and the heater core.
Has anyone else had this problem?

Any help on this would be greatly appreciated!

 

blend door stuck possibly.

 

I called a Ford dealership and they said it was my evaporator freezing up... parked it for the night and everything was fine the next morning.