2014 chevy silverado LT
Everything in my HVAC system works just fine.
Except, when I switch to defrost. I can tell that the air is being diverted to the defrost vents as I can feel some air coming out of there. However, I am certain that not all of the air is coming through like the door is not all the way open. I can hear the high pitched sound of a bunch of air trying to fit through a small space.
Think the actuator is out or there is something that has been dropped down the vent that is blocking the door from opening all the way.
Any thoughts on if it is one of those or something else? And how to fix it?

 

I believe that you are correct. The actuator is likely defective now. Its also possible that something is blocking the door. If you have an actuator above the gas pedal, on the climate control box, that is likely the actuator that might not be working properly.

 

Posting an update:

When I originally bought the truck in the summer I never did check the defrost. Winter came and defrost didnt work. Took it back to the dealership and they looked it over and said for them to fix it I would have to pay out of pocket because it was not covered by warranty. So I have gone 3 winters with little to no defrost. My AC in the truck went out last week so I have decided to actual dedicate energy to getting the AC and the defrost working.

Long story short, what the dealership said would cost $1000+?

I ended up just resetting the A/c system by pulling the fuse out for a bit, putting it back in, waiting a couple of minutes, then turning the truck on and the defrost door is now opening.

So before you go to replacing doors or actuators, try resetting the system this way first.

Hope this helps someone.