Prostar only blowing air thru Defrost

I have 2010 prostar, about 3 weeks ago the only air comes thru the vents for the defrost. I can change the temp and fan speed, and that works, but the it doesn't change the location were the air comes out.

 

I printed the picture, where is this located on the truck? Which do you recommend I try first? In the picture there is 2 actuators.

 

i have located on the truck what is picture in the link. Is there a way to test the actuators, or the head controls?

 

thank you I got it fix. The problem was the mode actuator, but I also replace the blend door actuator.