Searched for "clicking" on the forum and returned a few threads.
https://www.chevyhhr.net/forums/prob...licking-40609/ seems to suggest it might be the fan motor.
https://www.chevyhhr.net/forums/prob...-airbag-60625/ state fan/door issues

I didn't inspect the cabin filter for debris.
It's my mothers car and I have yet to check passenger side airflow, but the AC/HEAT work fine and it blows like normal on the drivers side.
Will have to check this out tomorrow.

Was wanting to see if anyone had any ideas before I went Easter egg hunting. I tend to break things when I go digging without an idea of what the issue might be.

VIDEO:

 

Yep the blend door actuator is toast!

https://www.rockauto.com/en/catalog/...actuator,10721

 

Someone’s knocking. Let em in ! 😁

X2 what Oldblue said.

 

Has the cabin air filter ever been changed?
Is it when you turn the fan on or when you change modes?
Why are you turning the heat all the way up?
When you turn recirc on the AC turns on and you can only blow in the face.

 

Thanks. Will get one this weekend!

Not to my knowledge, but I will look into changing it when I replace the actuator.
When I change from outside to inside circulation is when it comes on(fan has to be on though). Changing speeds while the recirculation setting is on doesn't cause the click, but it will when I change it to the outside setting then back again, it does.
The heat is just me being an idiot and because it's cold. Not sure why I kept touching the heat knob. It doesn't have any bearing on whether it clicks or not. It still came on when it was on the opposite(cold) setting. So it seems like a vent door issue.
I will do some more tests tomorrow. I only spent a few minutes tinkering with the knobs.

 

Our 2011 with 90,000 Mi does the exact same thing. Will knock anywhere from 8:00 to 16 times, or not at all. The first year, it did it all Winter and quit when the weather warmed. Now it does it all year long. Once that door is done announcing itself everything works fine. We're just living with it.

I read somewhere about how it could need to be calibrated and the procedure for doing so, but I don't remember where

 

disassemble / assemble what you can reach without dismantling the dashboard.
A visual inspection will reveal the cause.
Simultaneous cleaning + filter replacement.

There is obviously something slowly moving in violation of the geometry, and the fan beats this "something" while this "something" makes its movement to it extreme position.

 

There is a 'redneck' fix for this, haven't tried it myself but it sounds like the easy way to go.

 

That is to correct a warped duct not to replace the actuator.

 

There are not short cuts!