No 12 volt power to tow package trailer outlet plug

[samuel_weiner]

I have a 2020 model x, I installed a P3 brake controller. The trailer brake system requires 12 volts power and we are not getting power from the factory plug in. The brake controller recognizes the trailer but we are not getting any power. Any ideas? Is there a fuse that needs to be installed? Any help is greatly appreciated

 

[scottf200]

Have you tested the pin (4) directly.

More ideas here:

Tesla stopped supplying 12V power to the aux pin of the 7 way - Fixed!!!

Hello to Model X owners with Model X manufactured on or after March 6, 2018 and no power to the aux pin of the 7 way trailer connector, I purchased a Model X-100D on February 2, 2018 for delivery March 22 of 2018. I was fortunate that with a build date of March 6, 2018 I got the new MCU...

teslamotorsclub.com

One helpful detail: The 12V aux pin is supplied by a 15 Amp fuse number F131 in the frunk.
Another detail: There is a Fuse in the Aux box by the right foot of a right hand drive car
fuse F308 Jcase 30 Amp.

Yet another note - The 12V aux power is only supplied when the car is in DRIVE or another selection
where the High Voltage bus is active!!!
So, in an unattended car that is off there will be no power to the 12 V aux pin.

 

[ewoodrick]

Where is the brake controller getting its power from?
How many pins are on your factory plug? How was the controller integrated?

 

[samuel_weiner]

Solved, had Tesla Service repair and they noted the following:

Confirmed customer concern of trailer harness not receiving 12v. Found trailer harness connector
needed retrofit to updated wiring configuration. Upon rewire found 12v now present at trailer
harness. Trailer system nominal at this time

They tried to charge for the service but it was clear that this never worked. Kinda strange they would not just fix issues that were clearly defects from production.

 

[NewbyMaybe]

Probably an override required from a supervisor to void the fee. Shareholders like the cash flow generated by that sort of thing.

 

[Misterbee]

I have had my Y for over a year, and just now got around to connecting a trailer. Sure enough, no power.

 

[lonnielevi]

I have had my Y for over a year, and just now got around to connecting a trailer. Sure enough, no power.

That may be a different issue.

The change to 16V lithium ion to replace the 12V lead acid means no power to the Aux pin (pin 4 on the diagram above).

They could have installed a DC-DC converter that lowers voltage at the pin, but chose not to for whatever reason.

To me this is a safety issue. If you can’t keep a trailer’s 12V battery topped off, you will be in trouble in a breakaway situation.

Can anyone confirm if the Aux pin is also dead on the newest refresh Model X with the 16V lithium like the Model Y?

 

[ShawnA]

Hi @lonnielevi ,

I can confirm the Aux pin is dead in the refresh Model X.
Mine is a September 2022 Long Range.

After dancing with the Service Center, they confirmed that all cars with the 16V lithium battery
have a dead Aux pin.

They also said that Tesla has a retrofit in process to make the Aux pin live for 16V lithium battery vehicles.

Sorry for the large size, but it's good news...

Shawn

 

[lonnielevi]

Hi @lonnielevi ,

I can confirm the Aux pin is dead in the refresh Model X.
Mine is a September 2022 Long Range.

After dancing with the Service Center, they confirmed that all cars with the 16V lithium battery
have a dead Aux pin.

They also said that Tesla has a retrofit in process to make the Aux pin live for 16V lithium battery vehicles.

View attachment 999765

Sorry for the large size, but it's good news...

Shawn

Thanks @ShawnA

I emailed [email protected] to threaten arbitration for this and they kicked me over to my local service center where they wasted an entire day with my car for whatever reason. They said they were being told by engineers that it’s by design. Which yeah, duh, you’re gonna fry a 12V on the other side if it’s pushing 16V. But the 7 pin is an industry standard and this needs to be fixed ASAP. It should have been “engineered” with a DC-DC converter that lowers the voltage. Just insane, IMO.

 

[Misterbee]

That may be a different issue.

The change to 16V lithium ion to replace the 12V lead acid means no power to the Aux pin (pin 4 on the diagram above).

They could have installed a DC-DC converter that lowers voltage at the pin, but chose not to for whatever reason.

To me this is a safety issue. If you can’t keep a trailer’s 12V battery topped off, you will be in trouble in a breakaway situation.

Can anyone confirm if the Aux pin is also dead on the newest refresh Model X with the 16V lithium like the Model Y?

I’m sure that that is an issue but that’s not exactly what I’m seeing. I tried connecting two different trailers to my 2022 model Y, and both times the lights on the trailer did not light up, and the trailer mode icon in the car turned red.

I even tried checking the seven pin connector with both volt, meter and tester, although it’s really hard to use those tools in such tight quarters. Neither one yielded any indication of current.

So either I am doing something wrong, or there’s a different problem with my car. I tried getting mobile service to come out just to tell me if darn outlet is working, but they insisted on converting it into a service center appointment. I’m not really excited about that.

Any and all suggestions are welcome. I could just wait for this alleged fix that is in the works, but I’m not even getting trailer lights to light up.

 

[ShawnA]

Hi @Misterbee ,

Your problem is different from what is being discussed above.
You have additional problems.
The easiest start to testing is a Curt 7 pin trailer tester or a similar device.
7-Way RV Blade Connector Tester
You will be able to see what works and what does not work.
Plug it in and turn on the hazard lights and see if the lights in the tester light. You may need a helper for some of the tests.
It is likely from your description that there is a bad or missing ground connection to the trailer if no lights function.
The “good news” in your case is the red lighted trailer icon in your car. This means that the car at least recognizes that there is a trailer present and connected to the car.

Does your trailer use LEDs or incandescent lights? Some systems have trouble identifying a trailer with LEDs because they don’t see the resistance they are expecting.

Mobile service may be able to help but your best start would be getting the tester mentioned above to see what may work.
The testers are available at Amazon for less than $20.

Please keep us updated on your progress.

Good luck,
Shawn

 

[Misterbee]

Hi @Misterbee ,

Your problem is different from what is being discussed above.
You have additional problems.
The easiest start to testing is a Curt 7 pin trailer tester or a similar device.
7-Way RV Blade Connector Tester
You will be able to see what works and what does not work.
Plug it in and turn on the hazard lights and see if the lights in the tester light. You may need a helper for some of the tests.
It is likely from your description that there is a bad or missing ground connection to the trailer if no lights function.
The “good news” in your case is the red lighted trailer icon in your car. This means that the car at least recognizes that there is a trailer present and connected to the car.

Does your trailer use LEDs or incandescent lights? Some systems have trouble identifying a trailer with LEDs because they don’t see the resistance they are expecting.

Mobile service may be able to help but your best start would be getting the tester mentioned above to see what may work.
The testers are available at Amazon for less than $20.

Please keep us updated on your progress.

Good luck,
Shawn

Thanks for the clarification, and my apologies for the thread drift. I’ll try to find a better form for my questions.

FYI, I have already tried the tester you listed above. It does not light up at all with the flashers.

And I have one trailer with LED and one with incandescent. Neither one lights up.

 

[ShawnA]

Hi @Misterbee ,

You need a Service Center Visit...
They may not be able to fix everything but you should be able
to leave the service center with lights and turn signals.
Electric brakes take additional time and equipment...
The "live" 12 volts for battery charging will take the promised retrofit in the future.

There is plenty of work for the service center on your car now...

Good luck,

Shawn