Weird sound on start up from hvac I believe

So when I start up the vehicle no matter if its been running for awhile or cold start if I have the heat or ac enabled. The sound sounds like a winding sound like its trying to open something or actuation of something. It sounds like it is coming from the center consol near the air vent, the sound only last for about 10 seconds then its over until I switch from floor to upper to defrost air control setting then I hear it again. I understand I probably sound crazy trying to retreat what it sounds like but if anyone can help that would be awesome.

 

It is the servo motors moving the dampers into the appropriate position for your vent settings.

When you shut the truck off, after a minute or so, it will move them into some default position, so when you start back up they have to move back to where they are set in your settings.

I thought I read somewhere that the reason it switches position after you stop is to keep condensation from remaining in the coil housing where it can start to grow crap and start smelling musty.

 

So I'm guessing mine is just not lubed up or running a little rough. Well I found an entire new servo assembly for like $50 so I'm gonna drop that in and make sure the gears are lubed up. Thank you.

 

Probably just a little grease on the gears - they are nylon. In 300k miles on my 2008, I only had one servo fail on me and that was at about 240k miles.

 

I’ve never noticed this, I’ll have to pay closer attention next time I start up the truck!

 

Perfect thank you so much for the info. So I tuned the truck on with my ear next to where the servo motors are and sure enough its right there and happens when switching the air flow controls. It sounds like one of the gears rubbing on something. And when you shut the truck off and sit in silence for about a minute you hear the gears reset back to starting position. Thank you again.