Heater/Ac ducting control

[Ziegelsteinfaust]

After a couple of years of just ignoring the poor wiring, and heater issues of my truck. I have decided to fix it so I can sell it to fund the purchase a Suburban or a wagon. My son, and I need a vehicle with more interior room for our winter trips.

So while the heater now works alot better, and shuts off fully. I can not switch the places the air comes out of. If i move the lever. It mostly still comes out the bottom.

Where is a good place to start to look for the issue?