Hey Woody.
You're not the first nor only thread watcher who gets their popcorn out with each new instalment of the series.
Unfortunately for me I am not interested in continuing this series.

I want to end it finally! It's been going on far too long. The noise has been there now a year and a half and though I
have finally located the specific region it is coming from I still don't know its precise location nor what is causing it.

Lexus Canada is of no help and neither is my dealer as I have mentioned earlier in this thread.

 

Thanks Tootsall that was very helpful.

I had a good hunch that wires were bundled together and multi-functional.
Everything you said makes sense.

But it still doesn't get me closer to finding out the source of the noise nor how to stop it.

I have been operating under the assumption that an electronic signal is being sent from somewhere to some
part so the part can do something.
I have also been operating under the assumption that the part is not cooperating.

Sigh. I still would like to know how I should proceed now?

Because:
1. Removing the gas cap would not be helpful.
2. The noise doesn't have anything to do with the trunk door (release mechanism), because I have opened the door and the noise continues.

 

First when it happens while driving open gas door just to see if noise changes. Also by your putting your hand in there and moving things around it may never happen again.

 

Thanks alextv.
OK I'll do that with the gas door.

re: putting my hand in there and moving things around...
At this point I don't simply want to stop the noise.

I want to know what is causing the noise, because I don't think this is normal (the sending of the signal).

 

For what it's worth I still think it's a mechanical noise, not electrical (at least mechanical should be easier to track down than electrical). Did you check the private message I sent a couple of days ago? Something is just barely touching or rubbing against something else sufficient that the (admittedly tiny) engine vibration causes the motion and creates the buzz At this point I'd suggest to pull the trunk lining out on that side so you can poke and prod around while the engine is idling and the noise being generated. If you watch this video on installing a custom light bar on the back (especially the second half of the video), you'll be amazed at how much "stuff" there is hidden behind those panels and any of it could rub against any other item. Good luck.


ps: I guess I don’t have to say to do this outdoors so you don’t gas yourself with carbon monoxide! (but I said it anyway)

 

I believe I am finally making some good solid progress!
Photos will be uploaded shortly.

Here's what I did.
I removed the inside cover panel on the left side of the trunk.
This revealed some wiring and a bunch of other stuff.

One mysterious part is pink in color. It is very loose and I would like to know its function.
Part of it is held loosely by a white clip.

There is a grey circular 'plug' that has no obvious function. What is it for?
The inside of the plug is not attached to anything!

I was surprised and disappointed to see so much wiring just wrapped with electrical tape.
Probably half or more of the wiring in the car is the same.
I guess Lexus feels, 99% of the owners will never see this so what's the big deal about it?
Looks very amateurish to me.

I started to wrap the wiring bundle inside the 'cup' as recommended but then when I tested its
movement I guess I had put too much cloth because the trunk door wouldn't close.
So I removed the cloth.

Then I made a huge discovery!
As I was moving around some stuff I heard a rattle.
Not the same Geiger sound but still something was moving.
At first I thought it might be that loose pink part.

On closer inspection it was a small, square piece of velcro attached to a plastic part.
The plastic was sitting loosely inside a housing.
This velcro part was being used to hold down part of the inside cover panel of the trunk!

My hunch right now is that it is this small 'velcro part' that may be making the noise I'm trying to fix.

Lord only knows (and this is the part that really puzzles me) why it will sound for a few seconds/minute
and then stop entirely. No difference where I am driving. Sometimes it won't start again for weeks!
It just doesn't make sense.

For the time being, I took some electrical tape and taped the velcro part down to its bracket so it wasn't loose.

Photos coming soon.

 

Here are the mysterious parts.



Pink part

Pink part..

Pink part...

Velcro square

Velcro square..

 

That plug hides the hole big enough for your hand to access the manual gas door release. Ok I see it now the pink part is the release for you to pull.

 

🍿🍿

 

For those who would like to see a video on the ES manual fuel door release details, Northside Lexus's Melissa O'Connell's "How to Locate the Emergency Manual Fuel Door Release on Lexus Vehicles - Tech Tip Tuesday" video covers all Lexus vehicles current as of the October 2022 release date. The ES portion starts at the 6:40 time mark:

 

Well we can now eliminate the gas door/cap theory.

Today the noise came back briefly but I had time to open the gas door and also the gas cap before the
noise stopped.
Neither the gas door/cap had any effect in silencing it.

 

Can you take a video again from the trunk?

 

With the inside cover in trunk removed is the sound louder or the same. Could it be coming from left rear speaker?

 

I am going to keep my phone with me in the car ready to record the next time I hear the noise.

The last recording I made was taken still inside the car from the back seat just next to the back
speaker (left side).
That's when I thought the noise was coming from what I later learned was the seat belt assembly.

Inside the trunk, listening at the cable/cup location the noise is the loudest so far.

 

I haven't had a chance to hear the sound up close yet with the inside cover removed.
But it was plenty 'loud' even with the cover still on.

Where is the left rear speaker?
I can clearly see the rear right speaker. It is huge and out in the open. I didn't know there was a left speaker.