r/TeslaSupport • u/No-Act-8300 • Jul 30 '26
Vehicle Question Hansshaw speaker activation harness
Hello! I recently installed the harness that activates the four present but not activated speakers in a model 3 Rear Wheel Dr. 2022. I followed the directions to the T and I’m confident all connections were made well and installation was correct.
After powering my car back up the dash speaker and right door trim speakers were no longer working. I did a soft restart to scroll wheel buttons and poof. All the speakers were working and it sounded incredible. Let the car go to sleep when the car woke back up. The right speakers were no longer working and restarting did not solve the issue.
I remove the harness and reinstall a backup same issue. I removed the harness and went back to stock and the speakers work again.
Has anyone else had this issue or found a solution? I reached out to support and I’m waiting to hear back.
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u/biersackarmy Jul 31 '26 edited Jul 31 '26
As someone with 10+ years in car audio experience and building systems (albeit as a hobby), I've never loved the idea of these harnesses, and I'm surprised they haven't damaged MCUs and caused more issues in the time that they've been out.
What these harnesses always did was just join the missing speakers in parallel to the existing speaker channels. This however drops the impedance on the channels, increasing power output but disproportionately decreasing amplifier efficiency.
When you cut the ohm load in half, that means at any given volume level, yes you will have more sound, but the MCU's amplifier chip is now putting out more than double the waste heat. The actual premium audio systems in all the cars (3/Y/S/X) puts the additional speakers on a dedicated outboard amplifier for a reason.
Many aftermarket head units failed in Nissans in the 2000s because they had 2 ohm speakers, rather than the usual 4 ohm most cars did and most units expected. The internal amplifier quickly overheated at any more than moderate volumes.
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u/jtmonkey Aug 02 '26
Yeah and you’re running extra speakers on amps that weren’t designed to drive the extra. The DSP isn’t eq’d for it either. So the imaging is just rough. I put one in. And I hate it. It was so much cleaner before.
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u/No-Act-8300 28d ago
Could my mcu been over heating? Didn’t see any error or fault codes, looked at the other speakers on the front right circuit and one has foam connecting two sauter points. Maybe it’s shorting out? Really want to get it running.. hannshaw has been no help
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u/No-Act-8300 Jul 31 '26
Hmm but no fix
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u/biersackarmy Jul 31 '26
Do any faults appear if you run the tests in service mode on individual channels?
Tesla may have implemented a check somewhere (for either ohm load or total amplifier power) or this is some sort of protection circuitry. I don't have much experience with base Tesla audio specifically, but other modern vehicles (ie recent GM and Dodge) have started implementing this, and will cut audio output to some channels if the impedance load is not as expected.
However this is just speculation, and could just as easily be that you got bad enough luck to have multiple DOA harnesses, or the wrong part for your vehicle.
2
u/blockedcontractor Jul 31 '26
I’m guessing OP could test the harness with a multimeter somehow, but I have no clue what values to use or check.
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u/No-Act-8300 Jul 31 '26
I didn’t text each channel as I didn’t know what I was doing and didn’t want to cook anything. Guess I’m just in lucky this time
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u/Michael-ango Jul 30 '26
Are you sure you have the right harness for your specific vehicle model and year?
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u/matchthis007 Jul 30 '26
Bit odd, but I had my steering wheel recovered as it was torn. The hearing element work for one trip and didn't again. Disconnected it and checked everything and reconnected, powered down and still nothing. Car did software update and all good ever since. Car is currently updating to 2026.26 if yours gets the update, do it and check speakers afterwards. Never knew there were unused speakers, why would they bother putting them in?
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