Lumpyd

I've been having a problem for a long time with my 2006 a4 heat. Car runs at normal temp and the water pump is good. I've cleaned and back washed the heater core. It holds pressure. And when I turn the heat on, I get about 3 seconds of hot air. I have taken the glove box out and checked the actuators. The top 2 seem to be working fine. I cant seem to get the bottom one to do anything. Not sure if I am just not hitting the correct heater control buttons. Took the actuator out and took the casing off, and it looks fine and moves freely. What control should make it move?

The actuator i took out is attached to the pink arm