Simple reversible "UFO noise" killer

So I can't stand the "UFO noise" that this car makes. It's so loud, and has a discernible pitch that messes with me when I'm listening to music and whatnot. It had to go.

Ways of disabling it are pretty well documented, but usually involved destructive techniques like cutting the speaker cone. I didn't want to do anything destructive, or that couldn't easily be reversed.

I actually have more plans for this, to be realized over time -- my bare minimum goal is to add some controls to the cabin that let me toggle the speaker on/off, and/or reduce its volume. But we can go bigger. I've got most of the parts I'll need for the more advanced stuff I'm going to be trying, but I'll save the details for another time.

For now, I wanted to just disable it, in a way that's elegant, avoids shorting the leads (and potentially damaging the amplifier module over time) and in a way that I can easily undo and return to stock. Easiest way to do this would be to build a small inline 'dongle' that adds a resistor between the leads and disconnects the speaker, while not leaving the cable to dangle, or the speaker's connector to be exposed to the elements.

I looked through the technical docs and found the part number for the connector used by that cable:


It's a connector normally mated to lighting assemblies, repurposed to connect to the speaker here. That's annoying, since it means there's no official standalone connector from Toyota that it mates to. That's okay, though, as third party vendors have compatible mating connectors.

I found both connectors on Corsa Technic, and ordered a pair of each (you only need one of each; I bought an extra set for the future modifications I'm planning).



I also got a pack of 8-ohm 3-watt resistors. I don't know the wattage of the speaker/amplifier, but it can get pretty loud, and I was too lazy to go test it, so I opted for a higher value here just in case. Adjusting for higher/lower power is simple enough.

These are the ones I got: uxcell 20Pcs 8.2 Ohm Resistor, 3W 5% Tolerance Metal Oxide Film Resistors, Lead, Flame Proof for DIY Electronic Projects and Experiments: Amazon.com: Industrial & Scientific


I added the resistor across the leads:


You could simply heat-shrink this and call it done, since this is the part that actually makes the whole thing work.

I wanted to keep the speaker "connected" though, just to avoid the loose cable flopping around and keep the speaker connector sealed. I wired up the other connector (which will connect to the speaker), and simply bridged the leads on it, hooking that wire through the loop on the above connector. The two sides aren't electrically connected at all; I just linked them together like that to keep them held together.

Some heat-shrink later:


And installed in the car (with a bit more / too much shielding):


And boom, no more UFO sound, no error codes, completely safe (probably), and I never even had to remove the speaker. And if I want to undo it, I just remove the 'dongle' I made and reconnect the cable directly to the speaker.

 

One thing you may or may not have noticed by now is that the warning system on this vehicle is damned loud. Distractingly so. At the low speeds in which these devices operate, there's so little difference between the volume level of a hybrid (with no warning system) and a modern ICE vehicle of a similar classification, that the sheer volume level that is mandated of these devices specifically on EVs and hybrids is patently absurd. There is zero need for the warning system to be as loud as it is. If contributing to noise pollution and annoying everyone involved is your goal, it achieves it wonderfully! I look forward to hearing about your experience petitioning legislators to enact a mandate of acoustic warning systems on all quiet vehicles, electric or otherwise.

Either way, as my post might have implied for those reading closely enough, I have plans to replace this with a circuit of a design that's a tad more interesting, which doesn't involve just turning it off at all times, and for which I already have enough parts to begin testing soon. I'll be posting the results of that when it's ready as well, which might hopefully serve as some inspiration for those interested in doing something similar. Not just for safety concerns, mind you, but just the simple fact that there is a speaker there, being utilized quite poorly, and I must correct this.

In the meantime, there are plenty of people who are intent on simply turning the thing off, and no amount of "but think of the children!" is going to change their minds. There are already numerous threads about this (with as many repetitions of this same tired debate) describing a variety of destructive methods for doing so, which people have absolutely no qualms with putting into action. They will happily take a knife to theirs just to put an end to this insufferable noisemaker. The only thing new with this thread is that it shows a way of doing the job in a manner that doesn't involve stabbing your speaker cone or shorting the amplifier, and can be easily undone if the user changes their mind (or their vehicle changes hands).

Hope that helps

 

I was surprised by that too -- that's actually how it was stock. I felt a little silly with all the protection I applied to the dongle I made, when I saw the exposed wires on Toyota's.

I live in a pretty rural area with a low population where you pretty much need a car to get around. Pedestrians are rarely encountered here, bikes basically don't exist, and the ambient noise level is largely limited to crickets and birds, with the occasional hacksaw going somewhere in the background lol

That said, I know what it's like being a pedestrian in a big city too. Actually pretty fresh in my mind since I literally just got back from a week long trip spending every day walking around Los Angeles and San Francisco, with all kinds of traffic conditions. When you're in a place like that, all bets are off. Every car is effectively "too quiet", and the only levels that will make them loud enough to matter will contribute in a negative way to the already-overbearing noise pollution.

 

You're the one who brought that here. You challenged my position in bad faith so don't be surprised when someone responds in kind.

 

The language you used, and the smarm and sarcasm with which you appear to have delivered it and each response thus far, is used by people who have no interest in discussion and only desire to ridicule the idea. I hope you can understand how one might have their doubts about your sincerity.
That said, I'm perfectly fine dropping the debate as it's largely just devolved into chaos at this point.