noise behind passenger side airbag

I have a 2010 Tacoma and have what sounds like a nut that has come and moves back and forth, left or right, it moves when i accerate, brake or turn left or right. The sound is either in the vents or by the passenger side air bag.
I have remove the glove box, radio and even the fan but cant find what it is.
If it is in the vent would the object fall into the fan?
I search the threads but none seem to describe what I am hearing.
Any suggestions would be helpful.

 

i know the Tacomas have a rattle in the air box under the hood which is on that side and sounds like a rattle when idling or accelerating

 

fan

 

Pull fan and it is not loose and spin quietly. also the noise doesnt happen when idle.
Sounds like a marble rolling around over a wash board.

 

I thought it was the airbag assembly on my truck but eventually tracked it down to the wiring harness' plastic collar in the firewall. The fix is to put a thick piece of stiff adhesive foam (about 3/4" thick) onto a steel brace (it's next to the blower fan) to put downward pressure on the harness, thereby putting a bit of pressure onto that noisy plastic collar.

Toyota has a TSB for it (TSB-0106-10) if you don't have foam. Mine was just some kind of 3/8" windowstripping and I doubled it up. No idea how that combination of parts sounded entirely metallic but my dash has been silent as a mouse ever since.

If your rattle is what I was experiencing it's worst around 1600 rpm, although it occurred during a much wider range of engine speeds. Drove me insane.