So I believe my small on and off dash rattle comes from the HUD plastic window and surrounding leather frame. Do any forum members have an idea what I might be able to wedge in that gap to hold it tighter? Obviously it can not have any type of adhesive, because it will be impossible to remove. It is hard enough just trying to squeeze your hand in that small gap. Thank you again for any help!

 

Assuming your dealership will not help you out:

The foam circle feet you put on the bottom of things to protect furniture. They have various thickness and you can probably find your color.