Air flow for heat or cooling

The heater air flow direction moves around on it's own. In other words, I have flow to the floor, it moves to dash or defrost on its own. The one thing I do not get much of is defrost. The dash is the one place I get air almost all the time. Only direction is the problem, not how much air.
Note, I just saw the donation section, I will think about that. I have some other deep problems that will have donations. I would like to call this a test run for now. This is a first for me.

Roger

PS: The air will come out of the dash and the heat or defrost at the same time and so on