Model Y: Tesla OEM Trailer Hitch DIY

[MYLR_ON_CA]

Hi All,

With help from some of the existing posts (@gman99, @snyder). I have secured some parts to create harness that goes from the hitch to the Trailer ECU. I will post all the details here including part numbers once I am able to build a working harness including enabling trailer mode

I have couple questions:
1) does any have the info to help me figure out which pins in this Molex MX150 male connector from the harness has which of the seven functions from the wires coming from the 7 pin blade connector that’s on the hitch?

2) I saw Tesla TSB that said for 2021-2022 Y, ECU is required during Hitch retrofit (when done by Tesla). I did not see such TSB for 2023 Y. Can anyone confirm if Trailer ECU is already there in the bumper in the 2023 Y or not? If it’s missing then then the DIY effort may not be worth it because I can source the OEM hitch from eBay and build or get the harness with the hitch but Tesla probably won’t sell me the ECU here in Canada

 

[Callipygian]

Finally bought the correct towing ECU today from SC in LA.

Says its over the counter they didnt want to sell it to me at first kept saying how did i get access to the parts catalog i kept saying if u look at the TSB the url is listed so i went there. He said they cant sell to me and i kept saying the why does it say OTC. It was a battle then finally someone said he can buy it.

Ill try to install it this week not sure if the ECU needs to be programmed or not yet.

 

[Deaf Paul]

Following this with great interest. I have a 2023 MYP scheduled to be picked up in a few days.

Ordered a Drawtite hitch.

Planning to order the Tekonsha #119250KIT wiring harness. $209 + shipping to Hawaii.

Model Y Harness by Tekonsha

etrailers.com says this is the correct one and will work for my 2023 Model Y. I’m still worried. Do you know?

I am also trying to AVOID Tow Mode. I’m deaf and I do not care about any beeping noises when reversing. I do not want to lose my FSD in tow mode. This should enable me to avoid Tow Mode correct? Or will it still turn on regardless?

-Paul

 

[Callipygian]

Following this with great interest. I have a 2023 MYP scheduled to be picked up in a few days.

Ordered a Drawtite hitch.

Planning to order the Tekonsha #119250KIT wiring harness. $209 + shipping to Hawaii.

Model Y Harness by Tekonsha

etrailers.com says this is the correct one and will work for my 2023 Model Y. I’m still worried. Do you know?

I am also trying to AVOID Tow Mode. I’m deaf and I do not care about any beeping noises when reversing. I do not want to lose my FSD in tow mode. This should enable me to avoid Tow Mode correct? Or will it still turn on regardless?

-Paul

I recall reading somewhere about a change between 22 & 23 model year. People were waiting for something needed in 23 that wasnt needed in 22 leading to delays on installs. I dont recall what it was exactly. I think tow mode involves more than beeping but again dont recall exactly what, I figured since they designed it to be used with tow mode i might as well get it. Since youre going off brand to get tesla to add tow mode might be a feat per others. I was able to have mine added luckily. Others may know more specifically about tow mode usage and '23 wiring harness. I personally would just try to locate a used oem for ease in troubleshooting. Limited my need for specific knowledge when i had to start troubleshooting

 

[Deaf Paul]

I recall reading something about a part being removed from the '23 that's required for hooking up wiring for towing... I think I saved it in my notes... Lemme see if I can find it... Yep, here's a copy and paste from my notes:

Model Y tow hitch electrics
Harness:
“For cars that are built after 2022.. The Front Left Body controller is missing the chip to control/give power to the rear trailer 13pin plug....

Only way is to upgrade the body controller with the one capable with tow mode...

Attached is the bulletin for body controller upgrade...

I found out this after I bought a after market hitch and trailer plug...

But now I just wired a aftermarket 4pin trailer controller, and wire a 4 pin to 7 pin trailer plug and ran the wires the old ways”

https://teslamotorsclub.com/tmc/attachments/model-y-controller-pdf.951097/

 

[GWord]

Following this with great interest. I have a 2023 MYP scheduled to be picked up in a few days.

Ordered a Drawtite hitch.

Planning to order the Tekonsha #119250KIT wiring harness. $209 + shipping to Hawaii.

Model Y Harness by Tekonsha

etrailers.com says this is the correct one and will work for my 2023 Model Y. I’m still worried. Do you know?

I am also trying to AVOID Tow Mode. I’m deaf and I do not care about any beeping noises when reversing. I do not want to lose my FSD in tow mode. This should enable me to avoid Tow Mode correct? Or will it still turn on regardless?

-Paul

I would be extra careful here. Depending on what you are towing, my experience with my wife’s X is that the assisted drive modes can be unpredictable with a trailer.

 

[pipestem]

I would be extra careful here. Depending on what you are towing, my experience with my wife’s X is that the assisted drive modes can be unpredictable with a trailer.

I think he is saying he does not want to use FSD in tow mode. I think.

 

[Callipygian]

I recall reading something about a part being removed from the '23 that's required for hooking up wiring for towing... I think I saved it in my notes... Lemme see if I can find it... Yep, here's a copy and paste from my notes:

oh well thats the part i just got for my '22 and now my lights well electronics work while towing

 

[Deaf Paul]

oh well thats the part i just got for my '22 and now my lights well electronics work while towing

How much did the controller cost from Tesla?

-Paul

 

[DanDi58]

I think he is saying he does not want to use FSD in tow mode. I think.

No, I read it exactly as he typed - he doesn't want to 'lose' FSD in tow mode. And I echo @GWord concern about using FSD while towing - you're essentially blocking the rear camera whether you're towing a trailer or hauling a bike. I don't know how much FSD uses that camera, but I sure would not want to find out the hard way.

@Deaf Paul - I don't believe there is any way for the car to detect and automatically download a SW update that would install Tow Mode. At any rate, you always have the option to NOT install an update.

BTW - this is my 3,000th post! Congrats to me!

 

[Kurzweil]

I already wrote in painful detail regarding tow mode and its restrictions. There is an alternative approach should the above prove impractical. That same company has a similarly priced ZCI package that connects trailer lights wirelessly. It uses sensors placed along the Left/Right brake light and running light wires in the factory light-wiring near the taillights. I understand that it doesn't care what the voltage is and the signal can even be PCM. Needless to say, all driving features would work except for any modifications triggered by camera blockage caused by the presence of something behind the car. Around $180 on Amazon or $240 from Tekonsha, I believe. For your consideration.

 

[Callipygian]

How much did the controller cost from Tesla?

-Paul

197

 

[Deaf Paul]

I already wrote in painful detail regarding tow mode and its restrictions. There is an alternative approach should the above prove impractical. That same company has a similarly priced ZCI package that connects trailer lights wirelessly. It uses sensors placed along the Left/Right brake light and running light wires in the factory light-wiring near the taillights. I understand that it doesn't care what the voltage is and the signal can even be PCM. Needless to say, all driving features would work except for any modifications triggered by camera blockage caused by the presence of something behind the car. Around $180 on Amazon or $240 from Tekonsha, I believe. For your consideration.

I've been trying to source this Tekonsha wiring harness (which I linked in my above post) with no success for a couple of weeks now. Tekonsha themselves don't even have it in stock, and etrailers says it will be available again next year. No go on Amazon either. So maddening. Once a week I check the usual sites to see if somebody has 'em in stock and for sale... It's that time of the week - here I go again...

-Paul

 

[Deaf Paul]

Whoo-hoo, found an used one on ebay for about 90 bucks shipped. Fingers crossed.

-Paul

 

[rotarypower101]

Whoo-hoo, found an used one on ebay for about 90 bucks shipped. Fingers crossed.

-Paul

Anyone that has looked into these, are there any pros/cons to consider when selecting the OEM trailer module VS something like the tekonsha unit for an after purchase installation?

 

[Deaf Paul]

Pros for OEM: probably more reliable. Get trailer mode. No screaming back up sensors when in reverse.
Cons for OEM. Costs way more. Have to pay Tesla to install (I think). Trailer Mode forced upon you with no option to avoid or disable it. Loss of FSD.

 

[MarkCR]

Seems Tesla install would be much easier

 

[DanDi58]

Pros for OEM: probably more reliable. Get trailer mode. No screaming back up sensors when in reverse.
Cons for OEM. Costs way more. Have to pay Tesla to install (I think). Trailer Mode forced upon you with no option to avoid or disable it. Loss of FSD.

Installation is included with the OEM hitch.

 

[wlan0]

Big warning to new Model Y owners after August 2023 that have HW4 (mine is from September 2023/Fremont). The connector is now totally different for the trailer hitch wiring in the rear harness. The new connector is a little smaller (but similar body) and the pin-out is very different. Here is the part number on the connector:
160080-3006 (first row)
23193-21 (second row)

 

[wlan0]