Originally Posted by
riefdaddy
There are little felt strips that just wear with age that are supposed to provide enough friction to make the vent stay in place. The easiest and cheapest fix is to pop the vent out and place a small piece of electrical tape next to the felt. That is what I did and it works well. Another option is to peel the felt off, put a piece of double sided tape down and readhere the felt.
To pop the eyeball vent out you need a shoelace, or a thin piece of rope. You put it through the top of the vent and use a hook to pull in back through the bottom of the vent. Grab both ends and give a firm tug straight out and the ball will pop free. Installation is just pushing the ball into the socket until it pops in place.
You can google Miata vent fix to find a video showing steps on how to resolve the issue.