Dash rattle experience

I wanted to share my experience with some dash rattles in case it helps somebody else. I also have one issue I would appreciate help on if anybody has experienced the problem.

1. I had a slow (annoying) tapping sound coming from the dash, especially when accelerating or on rough asphalt. I eventually tracked it down to the speaker covers on the dash right by the windshield. I removed this trim and put some very thin felt tape on the c-shaped clips on the trim piece and on the plastic it attaches to. This solved the tapping sound. (No tape was necessary by the red or black clips.)
2. I had a sharp clattering noise on the passenger side. I found there was an unused wiring connector that was left unsecured and taped it to the rest of the wires (which were secured very well! Frankly annoyed Toyota decided to leave just one slapping around in there.)
3. I had a grinding noise coming from both sides of the dash. This came from the trim panels on the side behind the door (they're basically like a drum). I added mass to the panel and applied thick felt tape everywhere plastic could clatter and this mostly resolved this problem.
4. I had slow rattle by the passenger footwell. It turned out my glove box wasn't latching on one side. This was solved by slamming it shut.

Finally, I have an occasional buzzing sound from the passenger side. This comes from the vent trim for the side window defroster being loose. For the life of me, I can't get the thing to clip together. On the driver's side, the same trim piece attaches easily just by pushing up, but on the passenger side only 2 of the 3 will click together at a time. If somebody knows how to get this trim piece to work I would appreciate the help, for now I've wrapped it in duct tape...

 

An update:

I have eliminated the rattle that was reduced, but not eliminated by adding mass to the side triangular trim. I believe that the sound actually comes from the ducts inside the dash.

If you remove the trim and vent and press gently on the outside corner of the duct and let go, you can reproduce the springing/grinding noise. Since the triangular panel clips into a piece of trim that attaches to the vent, I suspect it was like a membrane amplifying the sound so adding mass dampened it.

I used some duct tape to connect the unsecured side of the vent to the top and now it's silent. Probably adding mass to the triangular trim was not necessary. (I did have a click sound from the plastic hitting the metal inside the dash on the passenger side so it was still worth poking around in there with some felt tape.)

Also, after hitting a pothole the defroster trim fell off on the driver side as well. I guess the answer to my question above was "the three little clips just don't work very well". Both sides are now clipped into place and wrapped with duct tape and they haven't been a problem since. (I was able to finally get the passenger side to clip correctly.)

All around, having seen the causes of the various rattles, I can't complain about the actual build quality of the interior: everything is bolted or clipped together very well. I am annoyed at whatever engineer or designer decided attaching a duct to the defroster should need four separate pieces clattering around instead of two or who decided to have the ducts secured only on one side and not the other. (I suspect this is to cut costs, all the complex shapes are manufactured separately and clipped together.) Toyota also should really start putting a penny worth of felt under the speaker cover, this is a rattle I've observed on almost every Toyota product I've been in. I don't even fault them for the unsecured connector since that's probably used in all the other trims.

Hopefully this helps somebody else. I saw searching for the problem that others have complained of a rattle that was fixed by throwing a towel on the speakers and another by pressing on the vents. I would guess these are the same rattles I have experienced.

 

As the weather heated up, the tape fell off. I stuffed foam on both sides of the duct instead and it seems to be working.

Also, with warm weather, everywhere there is the gloss plastic now creaks and pops over rough pavement. (California is hot, it did it last summer too, but it's already doing it this year).

My last car was all cheap, hard, matte plastic. It was a boring sea of grey, but never rattled in 10 years. I the curse the "journalists" who kept demanding fancy dash materials.