Does anything need to be changed software side to enable a DIY added OEM trailer wiring module for Model 3?

[stopcrazypp]

thats my point. The tow bar isn’t there, its a separate ‘crash beam’ that gets removed and replaced with one with the necessary connections for a tow hitch. That same crash beam is on the 3 so why can’t they do the same? Heck thinking about it why go to the bother - why not just fit the original crash beam with mounting points for the tow hitch.

Can’t even be a homologation thing as you can pre-order with a tow hitch, just not retrofit so the models must be homologated for towing?


wonder if that’ll change for highland as they seem to be rumoured to be evolving how its built so presumably taking some lessons from Y among other things. So maybe it’ll be retrofittable then

In UK, there is a sticker that has a tow rating that apparently needs to be present on the car for police inspection (not just on tow bar). Perhaps every Y had that from factory, while not every 3 did? I'm not sure, maybe someone can post examples of stickers to compare.

 

[stopcrazypp]

The crash beam on the MY is exactly the same whether a tow hitch is fitted or not, there are 4 bolts at each end bolting directly into the mega casting, there is no such thing as one 'with the necessary connections for a tow hitch'. The existing beam is removed, the tow hitch is fitted using the same mounting points , then again the 'original' beam is re fitted over the top, i have personally done this.

The main difference between the M3 and MY is the rear mega casting, the tow hitch simply bolts to the face of the casting unlike a traditional tow hitch which would bolt to a chassis mounting point.

I suspect the M3 factory tow hitch installation has extra chassis strengthening which is why it cannot be retro fitted 'legally'.

As others mentioned the aftermarket kits are different from the OEM, so your experience with an aftermarket can't be applied to the OEM.

The OEM bar does not allow you to keep the rear crash beam, it is simply replaced by the trailer bar and must be discarded:

Do you need to reinstall the reinforced bumper bar for an OEM Model Y tow hitch?

Tesla sent out a mobile Ranger today to install the factory tow hitch. It was the Rangers first install so after bolting on the tow bar he tried to place the reinforcement bar over the hitch but it did not fit. The instructions on his laptop called for the reinforcement bar to be put back so he...

teslamotorsclub.com

 

[Cardo]

In UK, there is a sticker that has a tow rating that apparently needs to be present on the car for police inspection (not just on tow bar). Perhaps every Y had that from factory, while not every 3 did? I'm not sure, maybe someone can post examples of stickers to compare.

The VIN/weights sticker on the passenger side door sill tells you the weight limits of the car, including any towing capability. The M3 has a 0kg towing capability unless this is specced with the tow bar from the factory, in which case it has a 1000kg towing capability. All MYs have a 1600kg towing capability, whether or not the tow bar is specced from factory (it actually matters not, the tow bar is fitted at the SC, in any event).

I’m sure somebody must know why Tesla don’t register all M3s with towing capability, but this information certainly isn’t in the public domain.

 

[mbastian]

So I asked Tesla to activate Trailer Mode in my gateway config as I bought all the electrical parts from them. Of course they said no, and their reason was there is no option in my car config to do so.

I didn't believe them as the person I spoke to didn't know what Toolbox was. So I decided to buy a service cable (£30 from Amazon), and a 1-hour subscription of Toolbox 3 (£40 from Tesla), to check for myself. I won't go into too much detail in the thread, but of the visible configuration items, a handful of them were unlocked for editing (I'm assuming the consumer version is restricted). One of the unlocked items was for Trailer Mode. I switched it to the only other setting apart from 'none', sent it to the car, and...

View attachment 962555
View attachment 962556

...hey presto!

It cost me roughly £450 to source the parts, fit it myself and activate Trailer Mode.

Happy to answer questions about Toolbox in DM's.

I would like to enable that Trailer Mode via the ToolBox 3 with my Computer and buy the one hour Access for that. Can anyone help me where to find it in the ToolBox 3 Software? Thanks a lot, Michael

 

[MYLR_ON_CA]

I would like to enable that Trailer Mode via the ToolBox 3 with my Computer and buy the one hour Access for that. Can anyone help me where to find it in the ToolBox 3 Software? Thanks a lot, Michael

Service.tesla.com you can subscribe there to get access

 

[HCassidy]

So I asked Tesla to activate Trailer Mode in my gateway config as I bought all the electrical parts from them. Of course they said no, and their reason was there is no option in my car config to do so.

I didn't believe them as the person I spoke to didn't know what Toolbox was. So I decided to buy a service cable (£30 from Amazon), and a 1-hour subscription of Toolbox 3 (£40 from Tesla), to check for myself. I won't go into too much detail in the thread, but of the visible configuration items, a handful of them were unlocked for editing (I'm assuming the consumer version is restricted). One of the unlocked items was for Trailer Mode. I switched it to the only other setting apart from 'none', sent it to the car, and...

View attachment 962555
View attachment 962556

...hey presto!

It cost me roughly £450 to source the parts, fit it myself and activate Trailer Mode.

Happy to answer questions about Toolbox in DM's.

Out of interest what other options could you enable yourself in Toolbox, not talking about trailer mode.

 

[HCassidy]

I would like to enable that Trailer Mode via the ToolBox 3 with my Computer and buy the one hour Access for that. Can anyone help me where to find it in the ToolBox 3 Software? Thanks a lot, Michael

If you're nice to a service centre they might enable it for you. They enables Boombox for me recently.

 

[m.aicardi]

rManaged to get this done today. 2-hour job.

View attachment 955284

@doats1 :

I have to replace my trailer ECU.

I have looked at your pictures and I was wondering if you succeeded in making the job without removing the back bumper.

Thanks a lot in advance.

Marco

 

[doats1]

@doats1 :

I have to replace my trailer ECU.

I have looked at your pictures and I was wondering if you succeeded in making the job without removing the back bumper.

Thanks a lot in advance.

Marco

I don’t see how you can do any trailer work without removing the bumper.

 

[MYLR_ON_CA]

@doats1 :

I have to replace my trailer ECU.

I have looked at your pictures and I was wondering if you succeeded in making the job without removing the back bumper.

Thanks a lot in advance.

Marco

It not that hard to remove bumper but you need to do that to take number support off and install hitch.

 

[zoros]

Model 3 Owner's Manual | Tesla

Learn how to safely use your vehicle to carry accessories and tow a trailer.

www.tesla.com

 

[Garethrn]

Good morning all! I've just bought a M3LR and would really like to fit a tow bar. I've done enough research to know the legalities behind it, so I'd just like to discuss the parts and fitting aspects. @doats1 you seem to have exactly what I'd like! When you said that you sourced the parts for roughly £450, does that include everything needed (all hardware)? Also, did you source the parts new or 2nd hand and where did you source them from please? Sorry for all the Q's, as you'll be aware, it's pretty hard to find information on this subject. All help will be greatly appreciated.

 

[doats1]

Good morning all! I've just bought a M3LR and would really like to fit a tow bar. I've done enough research to know the legalities behind it, so I'd just like to discuss the parts and fitting aspects. @doats1 you seem to have exactly what I'd like! When you said that you sourced the parts for roughly £450, does that include everything needed (all hardware)? Also, did you source the parts new or 2nd hand and where did you source them from please? Sorry for all the Q's, as you'll be aware, it's pretty hard to find information on this subject. All help will be greatly appreciated.

£450 was for the parts for the car (Receiver, ECU, jumper socket, tow ball, nuts and bolts) and the software config. Everything was new and direct from Tesla apart from the actual tow hitch receiver. I got that from a salvage car because it wasn't available over the counter when I enquired. But I think someone recently got that part from Tesla as well.

To separate out the costs, I had to pay £40 for 1-hour Toolbox access to enable Trailer Mode in the gateway config and also about £30 for the diagnostics cable as well. The cable is probably cheaper than that now. I'd say the software part is optional but recommended; the car will still transmit signals to a lighting board without Trailer Mode, but it won't modify the sensors. So you'll get alerts as if you're always being tailgated or about to reverse into an object.

I already had the tools to fit it so didn't factor that in, but you won't need any special tools beyond what you'd normally have when working on a car. You should make sure all bolts are torqued to spec so definitely have a torque wrench ready. Also subscribe to the Tesla Service portal, as it contains all the removal and fitting instructions, as well as the right torque values. It's also free.

Hopefully this helps.

 

[Garethrn]

£450 was for the parts for the car (Receiver, ECU, jumper socket, tow ball, nuts and bolts) and the software config. Everything was new and direct from Tesla apart from the actual tow hitch receiver. I got that from a salvage car because it wasn't available over the counter when I enquired. But I think someone recently got that part from Tesla as well.

To separate out the costs, I had to pay £40 for 1-hour Toolbox access to enable Trailer Mode in the gateway config and also about £30 for the diagnostics cable as well. The cable is probably cheaper than that now. I'd say the software part is optional but recommended; the car will still transmit signals to a lighting board without Trailer Mode, but it won't modify the sensors. So you'll get alerts as if you're always being tailgated or about to reverse into an object.

I already had the tools to fit it so didn't factor that in, but you won't need any special tools beyond what you'd normally have when working on a car. You should make sure all bolts are torqued to spec so definitely have a torque wrench ready. Also subscribe to the Tesla Service portal, as it contains all the removal and fitting instructions, as well as the right torque values. It's also free.

Hopefully this helps.

I really appreciate this @doats1 , thanks a lot . I jumped ship from BMW and did a fair bit of coding with ISTA (BMW proprietary software), so I think that I should be ok with Toolbox. If it's not too much to ask, please would you mind providing a parts list / numbers for the OEM Tesla parts either by replying or PM (whenever you have time of course)? Thanks again mate, from the research that I've done, you seem to be one of the few that have attempted this the proper way, but on the same token, you are paving the way

 

[zoros]

I really appreciate this @doats1 , thanks a lot . I jumped ship from BMW and did a fair bit of coding with ISTA (BMW proprietary software), so I think that I should be ok with Toolbox. If it's not too much to ask, please would you mind providing a parts list / numbers for the OEM Tesla parts either by replying or PM (whenever you have time of course)? Thanks again mate, from the research that I've done, you seem to be one of the few that have attempted this the proper way, but on the same token, you are paving the way

Hi Gareth,
I take it you've spoken to Tesla(UK) about retro fitting a tow hitch, then?

Yet again - I have approached them locally in person and via the App and yet again months after talking to them initially - they tell me you can't fit one retrospectively because (a) you have to break into the wiring circuit and update the software (which they won't facilitate) and (b) it will invalidate the car warranty.

They tell me a hitch can only be installed pre-production??

Have you found this in your research?

 

[doats1]

I really appreciate this @doats1 , thanks a lot . I jumped ship from BMW and did a fair bit of coding with ISTA (BMW proprietary software), so I think that I should be ok with Toolbox. If it's not too much to ask, please would you mind providing a parts list / numbers for the OEM Tesla parts either by replying or PM (whenever you have time of course)? Thanks again mate, from the research that I've done, you seem to be one of the few that have attempted this the proper way, but on the same token, you are paving the way

Thanks but I can't take any credit for this! Here's the parts list from my invoice:

It doesn't include the receiver, which I got second hand as mentioned. The part number for that is 1137916-00-B.

You can order them via the Tesla app service menu.

I'm assuming you know this but fitting the kit doesn't make your car tow-legal. But you can mount things like bike racks.

 

[Garethrn]

Thanks but I can't take any credit for this! Here's the parts list from my invoice:

View attachment 1045478

It doesn't include the receiver, which I got second hand as mentioned. The part number for that is 1137916-00-B.

You can order them via the Tesla app service menu.

I'm assuming you know this but fitting the kit doesn't make your car tow-legal. But you can mount things like bike racks.

Thank you very much for taking the time to list these for me, it's greatly appreciated. I'll look into this a bit deeper on the weekend when I have a bit more time. I will attempt to source all of the parts and fit, and get back in touch to pick your brains about enabling "Trailer Mode" via Tesla Toolbox if that's OK with you of course? Thanks again

 

[Cardo]

Hi Gareth,
I take it you've spoken to Tesla(UK) about retro fitting a tow hitch, then?

Yet again - I have approached them locally in person and via the App and yet again months after talking to them initially - they tell me you can't fit one retrospectively because (a) you have to break into the wiring circuit and update the software (which they won't facilitate) and (b) it will invalidate the car warranty.

They tell me a hitch can only be installed pre-production??

Have you found this in your research?

This is the official line for pre-Highland M3s. The towbar had to be factory fitted and then they would plate the car with a 1000kg tow rating (910kg for earlier models). M3s that didn’t have the towbar fitted at the factory have a 0kg tow rating. There is no official retrofit so Tesla will not assist you with that. They will, however, sell you the individual parts, it would seem.

 

[zoros]

And when it comes to connecting into the cars electrics?
Don't you think they will spot it and invalidate your warranty?

 

[doats1]

And when it comes to connecting into the cars electrics?
Don't you think they will spot it and invalidate your warranty?

I’ve had the tow kit plus the software active since last August and my warranty is still intact.

Everything I’ve fitted electronically is directly from Tesla. I’m not sure who has been advising you but no wiring needs to be spliced or cut. The ECU connects to the wiring loom via an available connector.