Model Y Hitch Electrical Fault

[bigevil]

thanks in advance for any help.
have a 2021 Model Y w/ the Tesla factory installed tow package/hitch and getting an intermittent error where when in tow mode the icon turns red [which according to the manual indicates an electrical fault]. I'd say its red 50% of the time, and blue (functioning normally) 50% of the time.

Unfortunately Tesla uses the 7 pin plug and my bike rack (along with i believe every other one) uses a 4 pin so Tesla is saying they do not support this.

Anyone have any experience with this or tips to make it play nicely?
using a Kuat Piston Pro X

 

[bobkart]

I picked up an adapter at U-Haul for my boat trailer with the 4-pin flat connector. So far no issues, but haven't put a lot of miles on it yet.

Are you using such an adapter? And is Tesla saying that there's still an incompatibility with an appropriate adapter in the circuit?

 

[bigevil]

I am indeed. Tried 3 different adapters but sadly all no bueno. Tesla essentially said anything other than a 7 plug isn’t officially supported

 

[bobkart]

That would make me want to try to find 'something' with a native 7-pin interface that Tesla can't possibly say isn't compatible, and see if that gives any warnings. I wonder if a 7-pin outlet 'tester' could serve that purpose. I.e. it just has LEDs for each of the channels. No potential for 'mixing down' of the channels to fewer channels (six down to three it would seem). Plug one of those in, drive around waiting for the red icon (after first confirming proper operation of the tester). Leave the bikes off so there's no need for lights from the rack. If that doesn't expose any issues, I'd lean towards the bike rack as the problem. Seems unlikely that all three of the adapters you tried have something wrong with them.

Also, I would expect that, with the appropriate use of diodes, the Tesla should not be able to tell the difference between being connected to a native 7-pin trailer and through an adapter to a 4-pin trailer. I.e. the diodes would prevent any current backflow where the channels are mixed down for the 4-pin side. That seems to me (without thinking too hard about it) to be the only way the Tesla could detect an issue.

 

[bigevil]

That would be my thought too. Will try that and report back

 

[bobkart]

Got curious and looked up the pinouts for 4-pin versus 7-pin trailer connectors.

Trailer connectors in North America - Wikipedia

en.wikipedia.org

Turns out there's no need for any combining of signals when going from 7-pin to 4-pin. I had thought maybe brake versus turn signal were separate on 7-pin but not on 4-pin. According to the above Wiki page, they both combine brake/turn signals into just two conductors. The three extra conductors are Auxiliary Power, Electric Brakes, and Reverse Lights. I would hope that the Tesla is happy with nothing connected to those pins. It makes sense that a 7-pin-to-4-pin adapter would drop those three connections on the way to the 4-pin side. A continuity meter could be used to confirm that.

At worst, the Tesla could be trying to sense current on the Reverse Lights, and complaining if it sees none. Like if you had a burned out bulb. Then I guess the adapter would need to have a dummy load there. But I've not seen the red icon on my setup, so either my adapter has the dummy load or the Tesla doesn't check.

 

[bobkart]

I just checked my 7-pin-to-4-pin adapter and sure enough there are no contacts on the three terminals that don't have a correlate on a 4-pin interface. So no dummy load.

It's really hard to see how such an adapter could be considered faulty. It appears to be just four straight-through wires. Short of the Tesla insisting on some continuity through the backup light circuit, there should be no way for it to tell the adapter is in the circuit.

 

[cbrigante2]

I know Saris makes a 7 pin connecting rack with the tail lights as well. It doesn't look anywhere near as slick as the Kuat does, but if you were still in the return window for it, it might be worth a look?

Door County 2 Bike Motorized Hitch Rack, Electric Lift, Easy Tilt & El

Let Us Do the Lifting If you’re searching for the ultimate bike rack for eBikes, lookno further than the Saris Door County. Powered by your vehicle’s 7-pinconnection, the Door County is a full-service electric bike rack for electricbikes. Simply turn the key and press a button, and the Door...

saris.com

 

[mwenn1]

thanks in advance for any help.
have a 2021 Model Y w/ the Tesla factory installed tow package/hitch and getting an intermittent error where when in tow mode the icon turns red [which according to the manual indicates an electrical fault]. I'd say its red 50% of the time, and blue (functioning normally) 50% of the time.

Unfortunately Tesla uses the 7 pin plug and my bike rack (along with i believe every other one) uses a 4 pin so Tesla is saying they do not support this.

Anyone have any experience with this or tips to make it play nicely?
using a Kuat Piston Pro X

Yeah I am seeing this as well with my Piston Pro X, although I noticed yesterday that when it is daylight and no headlights are on the trailer mode is blue and working correctly but as soon as my headlights turned on as it got dark the trailer mode turned red. Lights on the rack still were working the turn signals were just going on a very fast blink instead of the normal blink rate. Cant figure out how to get it to stay blue with the headlights on

 

[bigevil]

I'm 3 different adapters in and no bueno!

 

[EVer Hopeful]

Can you maybe rent a small trailer from Home Depot ($40 a day) or U-Haul, but get one with a 7 pin connector. Drive around for a day and see if you get the same problem? If you do then Tesla can't fob you off any more

Plus, you'll be able to clean out your garage and get all the big items out to the city dump!

 

[bigevil]

Smart! love it. brb

 

[mwenn1]

Smart! love it. brb

what were the results?