Chevrolet Repair: A/C dual Climate Control, 2003 silverado ss, dual climate

Question
I have a 2003 Silverado SS that has the dual climate control. I have a loud clunking noise coming from under the dash on the passenger side. I can set the controls to any temp and move the selector from vent to floor to defrost and nothing stops this horrible noise. I even tried to set each side at a different temp setting and still doesn't help. What would cause this?

Answer
possible actuator motor (you have 3) , they are located in that area .

Is there anything not working properly in the hvac system ? temp not
changing or vents not changing when you move the controls ?

You may be able to reach you hand up and put it on the offending part
you can feel these and it is obvious when your hand is on it that you
found the right one. depending on which it is you may have to drop the
glove box down .