I have a 2005 Crossfire and just started to hear this noise. It appears to come from the glove box passenger side. When I turn the engine off, I hear a light clunk, rattle something it is quick but nevertheless you can hear it and it is annoying. A tech locally told me it is the air vent but it doesn't make sense. Any ideas? Thank you.

 

I think the tech may be right. I have heard the same noise. I believe there are dampers that open /close with the key being turned on/off. Try a different air/heat direction setting the next time you shut it down and see if the noise changes.