Improper Air Flow

I hope someone here has knowledge with the Hvac system on my 09 Avalanche....
Blower only blows hot on drivers side, passenger side works fine. When set to factory default it blows cold but then blows hot and stays hot if temp is adjusted.
So I had the Truck at the Dealer today to have it scanned and update the program....
Dealer
scan test B0413 04 temp control one feedback circuit open-passed
calibrate actuators. no codes returned
left side blows warm. inspect left temp actuator jerks when moving.

So, when I got home I changed the left temp actuator with a knowing good one....no change Hot
Reset the system again by pulling the fuse for the Hvac. After running for a few mins in default I adjusted the temp up and down and watched the actuator move with no issues.
I'm at a loss now.........

Well if you can interpret a service manual

Linky

But if you changed the actuator it may need to be calibrated, I thinkin since you said it's known working I'm thinking its used.

You may also want to check the connectors at the control module for loose pins.

Had to dig a little further tonight..... looks to be a broken air deflector on the passenger side air temp actuator. can't wait to do this repair

Looks like the actuator gets out of sync and breaks the air vent ( deflector ).... Working good now just in time for the cool weather

Glad you are making progress with it.  Good luck.