2024 Model Y with Tow Hitch, Low voltage brake voltage not present.

[CoolBuddy]

I checked the voltage with the wiring harness behind the driver side access panels and there is no voltage at the pins of the female receptacle. I had plugged in the harness pigtail and didn't get voltage. I also checked continuity of the red and black wires to the pins. Service mode showed no issues in the LV Distrubtion system. Any thoughts? I've submitted a service appointment, but hoping for any suggestions that could get this voltage without having to drive 1.25 hours each way on a weekday.

 

[ewoodrick]

Just wait to hear from the Service Center. I think that I've heard that many aren't enabled by default.

 

[ngng]

Lion vehicles do not have a low voltage enabled pin. It’s in the manual.

 

[CoolBuddy]

Lion vehicles do not have a low voltage enabled pin. It’s in the manual.

I had looked in the manual prior and requested the 4 pin pigtail connector, which the service center supplied to me.
1. Where in the manual is it? It's not in the area pertaining to the attachment of the pigtail connector
2. I don't think stingy service centers are going to give away even a $2 connector if it won't work anyway.
3. My understanding is there is only voltage supplied if the car has the Tow hitch option, so maybe that's where you are getting it from
4. I tried searching for a few terms to confirm your claim, but honestly could not find that in the manual when directly searching. Can you guide me to the section where you saw this.
5. Unrelated, but what happened to search in the car manual? I can search on my browser version, but in car, I didn't see any search, so was left just navigating around.
6. You say it's in the manual like everyone reads the manual from cover-to-cover, but most people will use it as a reference. For example, here is the pertinent section for this connection. There is no reference to the 12V pin being disabled in it.

 

[CoolBuddy]

Just wait to hear from the Service Center. I think that I've heard that many aren't enabled by default.

The frustrating thing is the nearest appointment is over 4 weeks out and it's a 1.25 hr drive for me to take it in. Mobile service was not an option (even when I requested the pigtail originally). I'm guessing then there is no easy fix to save this trip. I'll just keep using my accessory voltage from the center console run up to the radar detector for this trip haha.

 

[ngng]

I had looked in the manual prior and requested the 4 pin pigtail connector, which the service center supplied to me.
1. Where in the manual is it? It's not in the area pertaining to the attachment of the pigtail connector
2. I don't think stingy service centers are going to give away even a $2 connector if it won't work anyway.
3. My understanding is there is only voltage supplied if the car has the Tow hitch option, so maybe that's where you are getting it from
4. I tried searching for a few terms to confirm your claim, but honestly could not find that in the manual when directly searching. Can you guide me to the section where you saw this.
5. Unrelated, but what happened to search in the car manual? I can search on my browser version, but in car, I didn't see any search, so was left just navigating around.
6. You say it's in the manual like everyone reads the manual from cover-to-cover, but most people will use it as a reference. For example, here is the pertinent section for this connection. There is no reference to the 12V pin being disabled in it.
View attachment 1049143
View attachment 1049139
View attachment 1049140
View attachment 1049141

https://www.tesla.com/ownersmanual/modely/en_eu/GUID-A6D6CF75-C9CA-4140-97FA-341E27E3B4D8.html

 

[fiehlsport]

I think you're talking about two different things. The Li-Ion battery vehicles have a trailer brake controller harness in the footwell, this should be active. I just used mine the other day.

The 12V aux pin at the trailer hitch is not enabled, however.

 

[CoolBuddy]

View attachment 1049146

https://www.tesla.com/ownersmanual/modely/en_eu/GUID-A6D6CF75-C9CA-4140-97FA-341E27E3B4D8.html

I see where you were misunderstanding now. That's referencing pin 4 of the 7 pin connector next to the tow hitch:

My issue is with the 4 pin trailer brake controller harness next to the driver's footwell (at least in left-hand steering cars).

As a side, they have instructions to access that won't work. I'm sure the service manual correctly instructs how to access it, but I found a YouTube video. Glad I went there instead of the owner's manual first because it would've started the frustration earlier. You have to remove a couple trim pieces because there is a black clip holding the carpet in place. Pulling on the carpet like the instructions indicate will just frustrate people.

 

[fiehlsport]

Yep - You may have watched the video I just posted a few days ago actually

If the trailer brake controller port isn't active then it's probably a service issue.

 

[ngng]

I think you're talking about two different things. The Li-Ion battery vehicles have a trailer brake controller harness in the footwell, this should be active. I just used mine the other day.

The 12V aux pin at the trailer hitch is not enabled, however.

Ah yeah, I misunderstood!

 

[CoolBuddy]

Yep - You may have watched the video I just posted a few days ago actually

If the trailer brake controller port isn't active then it's probably a service issue.

I'm not sure if I saw your video or not. Can you post a link here or message me with it? Thanks!

 

[dcollet1]

I feel like we have been duped by Tesla. They suggest a tow package implying all of the standard functions will be available at the 7 pin adapter. NOT SO!
If your low voltage battery was Lead acid, the adapter would deliver low voltage (12v) back to the vehicle on pin 4. But, your model Y has been upgraded and is presumably is equipped with a LiFePo (Lithium Iron Phosphate) battery, rather than solving the problem, Tesla simply disabled voltage to pin 4, Hence, no power back to the trailer you would be towing, All other voltages and signals will work.

I discovered this last year. It became painfully apparent when I was unable to power an attached rear facing camera on the camper. The work around was to use the camper's battery for low voltage (12v) supply for the camera. As I state above, all signals, brake controller voltage back to the trailer will function as intended. Just the auxiliary power that should be available back to the trailer/camper is absent.

You would think that Tesla could figure a way to deliver the 12v back to the trailer with a dc to dc converter from the high voltage battery to enable power on Pin 4. It isn't rocket science...

 

[CoolBuddy]

I feel like we have been duped by Tesla. They suggest a tow package implying all of the standard functions will be available at the 7 pin adapter. NOT SO!
If your low voltage battery was Lead acid, the adapter would deliver low voltage (12v) back to the vehicle on pin 4. But, your model Y has been upgraded and is presumably is equipped with a LiFePo (Lithium Iron Phosphate) battery, rather than solving the problem, Tesla simply disabled voltage to pin 4, Hence, no power back to the trailer you would be towing, All other voltages and signals will work.

I discovered this last year. It became painfully apparent when I was unable to power an attached rear facing camera on the camper. The work around was to use the camper's battery for low voltage (12v) supply for the camera. As I state above, all signals, brake controller voltage back to the trailer will function as intended. Just the auxiliary power that should be available back to the trailer/camper is absent.

You would think that Tesla could figure a way to deliver the 12v back to the trailer with a dc to dc converter from the high voltage battery to enable power on Pin 4. It isn't rocket science...

This is about the four pin pigtail in the front for trailer brakes, but it is odd an electric car maker can't figure out how to supply an aux voltage to the 7 pin.