AC/Heater stuck on defrost?

This happens when the HVAC system loses the vacuum supply to the system. Check under the hood and looks for a small vacuum line that heads into the cab this will be the line that is broken. here is a guide that shows what I am talking about, and I have included the defrost actuator so you can check that out as well.

https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.