blend doors

I just had my thermostat and heater core replaced to fix a no heat issue. After driving around today I noticed that when I have the heat set to blow on my feet, it blows out of the defroster and not the feet. All other heat settings work as they should. Any ideas as to what would cause the heat...

Over the course of the last 9 months, I have followed all the posts related to no/poor heat in my 2008 3.7l 4x4 Nitro. My symptoms are: Very little heat after engine warmed up, but I do have some. I would say the air temp is in the 40-50 degree range even though it's below freezing outside...