Ok. Well I have had this 4runner a little over a year now. Last winter it had this sound, and is starting to have it again as it gets cold. It is driving me insane.
To me it sounds like a pen or pencil dropped in or near the drivers side vent in the far corner. It has ... i guess rattling sound. Best way i can think to describe it.

I took apart most of the dash at one point to try and figure out what it was, but didnt find anything.

Any ideas?

 

Remove the ducts and clean them out. You would be surprized how much crap is in there.

I have a noise in my fan box... seems to have sucked in some twigs or leaves...

 

any little thing that gets down and into the squirrel cage will make noise.

 

So the duct just comes out? or do i have to clean them where they are?

And thanks.