How-To Here's how to safely tap 12v power for add-ons

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_Travis_

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Sure can.



Looks like that's still the image there. Incidentally, see the above traffic -- it looks like Tesla is now populating that position; if you're updating, you might want to comment on that.
So unfortunately imgur won't let you modify albums, you have to delete and re-post, so there's now another album and hopefully people will find their way to it. But that image has been corrected.
 

ftenab

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Yeah, I briefly looked for documentation supporting that, but couldn’t find it. EU owner manual still doesn’t mention, and epg doesn’t show a new connector on the rear harness. Do you have anything that points to details?
I wonder if any european owner using trailer already in M3 could tell us where this red wiring is going on the rear trunk. Is clear is going from the VC-left to any rear point (laying from the left side doors down) , and the cable is very evident to find so it seems is the only one with this size (seems 14AWG) going to rear with big black tape package with other small cables less thickness.
 

McHoffa

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I can't seem to find out for sure, but is there a good 12V access point for accessories up front? I found this video, but someone said it doesn't exist in newer cars? I haven't dug into mine yet to see if it's there, and wasn't sure if it's the best spot available.


I don't care if it's always on or only on when the car is on, as long as it's not extremely difficult to access and safe to use. Somewhere under the dash or under the frunk would be best.
 

NR4P

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See my post 37 in this thread.
However since the introduction of Sentry, that line stays on often, instead of switching on and off.
Which means anything plugged in, stays on unless it has auto power down.

Sentry keeps the USB and accessory ports active.
 

mswlogo

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See my post 37 in this thread.
However since the introduction of Sentry, that line stays on often, instead of switching on and off.
Which means anything plugged in, stays on unless it has auto power down.

Sentry keeps the USB and accessory ports active.
If the car isn't "Sleeping" (i.e. Sentry) everything is on. Well, I'm not sure if the HVAC fans are on, probably. I tap 12V from the Rear Amp, so even the car radio Amps are on chewing up watts when Sentry is on.

I find it so odd that on a brand new design car it has to have everything on or nothing on and there is no state in between. When I first got the car I thought they just had not got around to it in software yet.
But since the introduction of Sentry mode, it seems inherent in the design that it's all or nothing. It's crazy.
 
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Hello, I'm very new here, registered today for two things :

- first, say thank-you to all people sharing their skill and helping better understand our car!
- second, ask some questions as I had a quite big problem while tried to upgrade sound on my M3 SR+.

I read almost the entire post about SR+ Upgrade, and decided to go on!
Yesterday, something went wrong while finishing the install, I think had a short in my amp line in (from the rear doors 4 " speakers) when I plugged the driver side line.
I'm pretty sure I made a mistake and short the line here... Immediately, the Penthouse power made two fast "clac" before shutting off. Then no power in the car except the frunk 12v battery and of course, not possible to run the car. Message "not enough 12v, the car may shut down suddenly"
I felt just... terrible. So I unplugged everything, and found a post talking about "fuses" in the Model 3, and as mentionned, waited 60-90 min. And the Penthouse switched back on!

My question now, sorry for that long explanation before : what if a short happend on the wires installed ( speakers, or worst, 12v from the penthouse) while driving ?
I hope there is a protection fuse that will NOT stop all the 12v from the Penthouse, or it's a real danger, does someone know something about that ?
Sorry for my mistakes, I live in Switzerland, speak french, and try to do my best in english.
 

eXntrc

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Hey @Turmix

You might want to check out this article from Mountain Pass about hard resetting the 3:

https://www.mountainpassperformance.com/tesla-model-3-hard-reset/

I followed this process to make sure the Penthouse was completely powered down while I worked on my audio system. I mention it for two reasons: 1 - because it would have saved you the trouble you ran into above and 2 - because of your question.

It was late when I was putting my car back together, but when I was going through the steps to re-engage the Penthouse I think I accidentally did it backward. Meaning, I think I reconnected the 12v battery in the frunk before I reconnected the contactors. The touch screen came on with all kinds of low power warnings, but it did come on. Meaning that I believe the car computer can run off the frunk battery for a period of time even if the Penthouse 12v has cut out. It may tell you to pull over immediately, but I don't think it's going to just shut off on you.

Having said that, if you truly have a hard short on the 12v line, to the point that you're shorting out the battery, that's obviously a huge problem. It sounds like this was just a momentary issue, but as always, do make sure to install a fuse or circuit breaker as close to the penthouse as possible.
 
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Hey @eXntrc !
I have seen this reset procedure, thanks a lot anyway! I think the problem was different for me: I didn't short the main Penthouse 12v. And my main power + have a fuse on it, as mentionned in the SR+ audio upgrade. (pic attached )

BUT when I tried to plug the line entry into my amp from the left speakers, the Penthouse disconnect and won't start back for 1 hour. Maybe there was a short in my amp, but not in the main power, just on the speakers line, even not sure about that. But I'm sure there was nothing with the main power at this time.. that's why I worry about a simple short in the speakers circuit can shut off the penthouse power and go to the frunk only. I think it's a security, but again, what happen if the amp die ans dhort when I drive for exemple, will it stop the whole car ?

Edit : accidentally, the power was on when I plugged the line entry in my amp, is it enough to shock the circuit ? Anyway, something happens and I still don't know what. And it's obviously scary..
Last possibility : I made this mount (pic 2 ) on my JBL a6004 amp to skip the LC7i, and maybe the problem is here ?
g109stagea4-o_other2-jpg.29293
 

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eXntrc

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Sorry I haven't been following the posts on the SR+ thread. I've been following the main aftermarket thread for a long time, but I missed your posts. If you want me to take a closer look at any of your posts, please feel free to let me know which ones and I'm happy to offer any thoughts I might have.

It's very strange that bringing the high-level inputs into your amp is what tripped it. Or at least that it seems that way. I only tapped the subwoofer, but @_Travis_ tapped the front speakers like you and didn't mention anything like this. I also know that he didn't power down the penthouse during his install, so he would have been in the same boat as you. You might want to review his final post to see if it gives you any clues:

https://www.travisllado.com/2019/05/tesla-model-3-stereo-part-9-summary-and.html

Has it worked for you at all yet? I'm just wondering if maybe the wires you are tapping for the front speakers aren't the same ones you think. Like maybe you're accidentally tapping a ground wire or something. I know the pinouts for the SR+ audio differ from the premium audio, so you might just want to double-check whichever diagram you're using as your guide.

I'm not sure if you posted the right picture 2 that you planned to. I see a picture that shows how you tapped the penthouse, but in your message you said something about a mount for your JBL?

The only unusual thing I see in picture 2 compared to what I've seen most people do is that you actually tapped the penthouse ground wire. I don't see any reason why this would be an issue, since the penthouse ground just goes to the chassis. But it's at least worth mentioning that most people I've seen so far have just used the same ground wire in the trunk that the original OEM amplifier uses. Since both of those wires you're running to the trunk are the same gauge and since they're both red... obviously make sure you're using the right one as ground in the back. I highly doubt you'd make that mistake, but since they're both red it's a valid thing to check.

With everything you've written, though, my gut feel is that there's a problem where you tapped the stock amplifier for the front. Since yours is the SR+, verify you're using the right diagram. If you have a loose speaker laying around, maybe even hook that up to the pins you believe are the speaker pins and verify you get sound out of them.

Best of luck @Turmix . Let us know how it goes!
 

eXntrc

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Something else that just dawned on me... This is the first time I've seen a separate ground wire on the high-level inputs.

1569242865988-png.29295

Usually high-level inputs are just + and - pins. The JBL A6004 manual says + goes to stock audio +, - goes to stock audio - and ground goes to the vehicle chassis. Just double-check that you've got the right pin going to vehicle chassis. Maybe even try it without this ground wire. The amp is already grounded through the much larger negative wire. I'm assuming the high-level chassis ground is mainly about reducing noise. I just wonder if something about the Tesla stock audio system doesn't like this approach of speaker audio signals being grounded to the chassis.
 
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Sorry I haven't been following the posts on the SR+ thread. I've been following the main aftermarket thread for a long time, but I missed your posts. If you want me to take a closer look at any of your posts, please feel free to let me know which ones and I'm happy to offer any thoughts I might have.

Thanks again, but I didn't post before, that's just somethings I read

It's very strange that bringing the high-level inputs into your amp is what tripped it. Or at least that it seems that way. I only tapped the subwoofer, but @_Travis_ tapped the front speakers like you and didn't mention anything like this. I also know that he didn't power down the penthouse during his install, so he would have been in the same boat as you. You might want to review his final post to see if it gives you any clues:

https://www.travisllado.com/2019/05/tesla-model-3-stereo-part-9-summary-and.html

Yup, I read his blog, still don't know what happened, the only difference is that I don't use any capacitor

Has it worked for you at all yet? I'm just wondering if maybe the wires you are tapping for the front speakers aren't the same ones you think. Like maybe you're accidentally tapping a ground wire or something. I know the pinouts for the SR+ audio differ from the premium audio, so you might just want to double-check whichever diagram you're using as your guide.

I'm not sure if you posted the right picture 2 that you planned to. I see a picture that shows how you tapped the penthouse, but in your message you said something about a mount for your JBL?

Oh, damn, I pulled it directly on the message, seems it didn't work, sorry. here it is :


The only unusual thing I see in picture 2 compared to what I've seen most people do is that you actually tapped the penthouse ground wire. I don't see any reason why this would be an issue, since the penthouse ground just goes to the chassis. But it's at least worth mentioning that most people I've seen so far have just used the same ground wire in the trunk that the original OEM amplifier uses. Since both of those wires you're running to the trunk are the same gauge and since they're both red... obviously make sure you're using the right one as ground in the back. I highly doubt you'd make that mistake, but since they're both red it's a valid thing to check.

You're right, and it's checked and double checked for main gnd and 12+

With everything you've written, though, my gut feel is that there's a problem where you tapped the stock amplifier for the front. Since yours is the SR+, verify you're using the right diagram. If you have a loose speaker laying around, maybe even hook that up to the pins you believe are the speaker pins and verify you get sound out of them.

Yes, that's maybe the problem!! About the tweeter on the driver side, I think there is no problem. it's purple and black as mentionned by @PLUR and very difficult to make a mistake because of the plastic connector. The right side was ok, and the amp worked fine with only the right plugged.. As soon as I plugged what I expected to be the line from the rear 4", plop!! Everything went wrong :(
Maybe the rear door 4” speakers: (driver’s (left) Black -, Red +)wires are wrong as it's common colors to power? I have to test that. Is it enough to plug a multimeter to it and see ? I don't have a speaker to try.. I checked and have no pictures of this side, I will do it as soon as possible to check..

Best of luck @Turmix . Let us know how it goes!
 

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Ok, I just take this picture.
1° please don't mind the tape on it, it was when I cut and secured a bit more the wires after it failed. the wires are welded, and protected with 2 layers of heat schrink tube

2° second thing, it seems to be 2 black wires from the same place, not true, it's on the picture. The 2 wires I used are twisted together. If it's not the right wires, it would be a good news as I could stop wondering what's happened..
 

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eXntrc

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(driver’s (left) Black -, Red +)wires are wrong as it's common colors to power?
I'm sorry that I won't be able to help you here because I haven't tapped this. I will say, though, that I'd find it very unusual for Tesla to use Red and Black wires for audio. Those are almost always reserved for power.

I have to test that. Is it enough to plug a multimeter to it and see ? I don't have a speaker to try..
A speaker would be much better to verify with, but in case you're accidentally tapping voltage here it's good to test with a multimeter first.
  1. Put your multi-meter on DC first and check Red and Black. If you see a constant voltage here on DC, you've got power and not audio.
  2. If you don't see much on DC, switch your multimeter to AC and play some music. You should see the voltage increasing as you turn up the volume.
 

eXntrc

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P.S. we should probably move this discussion to either the aftermarket thread or the SR+ audio thread since this thread was originally about tapping 12v power for accessories. If a moderator wants to move the last few posts, please feel free to.
 
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That's right, sorry if I asked my questions at the wrong place. I wasn't able to test the wire tonight, m'y multimeter is.... out of battery o_O
 

todd2fst4u

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Ok, I just take this picture.
1° please don't mind the tape on it, it was when I cut and secured a bit more the wires after it failed. the wires are welded, and protected with 2 layers of heat schrink tube

2° second thing, it seems to be 2 black wires from the same place, not true, it's on the picture. The 2 wires I used are twisted together. If it's not the right wires, it would be a good news as I could stop wondering what's happened..
I can confirm those are the driver side rear door speaker wires.
 
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I can confirm those are the driver side rear door speaker wires.
Thanks a lot!! And can you confirm too the Red is +?
That's a good AND a bad news because now I"m lost.
-My amp is dead, confirmed with another 12v power supply, the fuses burn at each start. I could buy another one, but maybe it's not the problem ? Why does it burn when I plugged the driver's door line in?
More, I read again the entire 33 pages of the SR+ upgrade poste and I see that' maybe the problem is about this amp needs the "fuse relay trick" to work with the penthouse power?
 

todd2fst4u

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Thanks a lot!! And can you confirm too the Red is +?
That's a good AND a bad news because now I"m lost.
-My amp is dead, confirmed with another 12v power supply, the fuses burn at each start. I could buy another one, but maybe it's not the problem ? Why does it burn when I plugged the driver's door line in?
More, I read again the entire 33 pages of the SR+ upgrade poste and I see that' maybe the problem is about this amp needs the "fuse relay trick" to work with the penthouse power?
Red is +
I’m not using the resistor and relay setup to power my amp and have no errors.
 
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Looking for 12v for a power trunk (the new Hansshow kit). The Teslasport and Hansshow videos show routing power directly to the 12v battery up front. Any reason not to use the 12v dc-dc convertor under the rear seat? Seems this would be negligible draw compared to a subwoofer/amp.
 
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Considering a trailer hitch is now available for the Model 3 (in other countries) I think it's clear they started adding a harness. Perhaps you might find the other end if you peek under the bottom or corners of the trunk liner. Might just be perfect for powering rear audio equipment!
Has anybody made any headway on locating where the trailer hitch 12V wire might be running through the trunk for a possible tap there?

Not a huge deal to have to wire from the front of the car, but if there is already a good wire in the trunk where I'm hoping to install my amp this could save a bit of time/space. Unless it's just easier to route from the front of course.