HVAC Issues

[6speed]

Recently changed the coolant. Making a long story short when I put the temp control on HI, the air goes from coming out the dash vents to the floor and defroster, as soon as turn off the heat it goes back to the dash vents.

 

[Yo Hoot]

Most likely the blend door vent gear stripped. Loads of posts on this site if you search.
also https://www.google.com/search?q=dod...j0i22i30l6.6398j0j15&sourceid=chrome&ie=UTF-8

 

[6speed]

I was uner the impression that once they messed up it was in one position and wouldn't move. Thinking it defaulted to defrost