2002 silverado air will not work

[Bryce Schaubert]

The air hasnt worked in my truck for a while so i wanted to fix it , i replaced the blower motor resistor , replaced the fuses , replaced the blend door actuator , and the air stops at 5 , and only comes out of the dashboard defrost vents. the 4th speed is starting to go out now too. i don’t know what else to do and i dont see anyone else with this problem. i hear the air blowing, and can feel the air coming out of the air filter spot in the cabin. any help will be appreciated