Not a lot of details.
Do you feel any tension while moving the knobs?
Do you hear any trap door movement?
May have snapped a nylon string that actuates the different doors. There are 2 of these, one moves a trap door from cold to heat and the other moves the trap doors from defrost to different lower position as the little icons show. These nylon nerves have a tendency to break when people attempt to change them before any heat has flowed through the system long enough to thaw out any possible frost that may have frozen these shut.
Here is a sample, easy job but you need a lot of patience and time.
Just checked it. The heat/cooling knob moves pretty easy. The position knob (goes from vent to floor to defrost knob) takes a little more effort. I actually don't hear a door opening and closing. I will have to check that when I get home from work tonight. Thank you for your time.
Did you figure this out my 2014 trax does the same heat blows cold till I turn fan all the way to high for a couple of secs. Then it will blow hot air. Without touching anything I can shut vehicle off and restart it and I'm back to cold air again. Any help is appreciated thanks