Well, after eliminating the center vent rattles (temporarily by removing it), I have honed in on one of my other incidental rattles.

It is the RH windshield defroster vent that runs along the base of the inside of the windshield.

When I hit substantial bumps, it will rattle.

So I'd like to understand how it is attached and see what I can do to secure it a little better. I suspect a clip or other fastener has failed at some point, but I don't want to go tugging on it and break it worse.

Does anyone know how these (there are two, LH and RH on either side of the solar sensor) come off and are fastened?

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Well, after looking at some photos of these vent pieces off the car (thanks eBay listings ) .... it looks like one simply pops off the center solar sensor, which is held on via clips, then the LH and RH halves of the defroster vents lift up from the center and are hooked into a nylon push rivet at the far end that it appears it will simply slip off from. So removal should be easy.

Good news there is that it doesn't appear one has to unscrew anything from underneath, which frankly I'm surprised.

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I have the same issue(2000XJ8). Hearing how they're attached i guess I see why they rattle. Not secured in enough. Any solutions to that?

 

I plan to pull them out, figure out why/where they rattle, then perhaps add some sort of insulating or deadening solution such as felt in key locations ....or maybe some flexible and reversible 'glue' to damp/secure said key locations. Will have to see.

In some of my past cars, if one were to take apart the dash, you might find small pieces of folded paper in strategic locations where I was eliminating a tiny point of contact

If their current mounting is the issue, versus something else more complex I discover once they are removed, I don't think it will be too hard to identify and control though.

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