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

[Durzel]

Seeing as the “missing structural component” seems to simply be that easily installed cross-member, I genuinely don’t understand why Tesla don’t register all M3s with towing capability, like what is done with pretty much all other cars.

Probably nothing to do with actual hardware limitations, moreover the sales logic in encouraging people to spec options they think they might need in the future up front.

For similar reasons you're obliged to choose how much memory and storage space you want on a phone or Apple laptop, etc at point of order, even though your requirements might be completely different during the lifecycle of the product.

It's not very consumer friendly, but I guess there is sales data that points towards people erring more on the side of caution and overspeccing, and thus spending more, than they would otherwise do if retrofit options were more freely available and supported.

 

[Adopado]

From what I’ve read, realistically no. It’s apparently to do with the homologation of the vehicle and is pretty much set in stone. But it’s odd that Tesla have essentially gone with two separate lots of homologation for cars with factory fit tow bars and those without.

I wouldn't be surprised if it was just an administrative cock-up when the cars were first imported. Maybe the Model 3 was fully homologated without the tow because of the different requirements in UK as opposed to USA ... then they subsequently applied for an add-on element tacked on just to cover the cars supplied with a tow package. I don't know how it works but I could envisage manufactures being allowed to do something like this but that such an extra wouldn't be possible to be done by private individuals so easily. [No evidence whatsoever ... just thoughts!]

 

[Mrklaw]

Seeing as the “missing structural component” seems to simply be that easily installed cross-member, I genuinely don’t understand why Tesla don’t register all M3s with towing capability, like what is done with pretty much all other cars.

from what I can find on youtube, looks like Y in the US is almost the same as 3 - it needs a structrual component bolting to the rear frame to take the hitch. Only the Y has a rear beam that neesd to be removed where it looks like the 3 just has empty space.

If thats the case its really odd one is tow rated and can get an official retrofit hitch, when the other can't. If anything its a tiny bit more complex job on the Y as you have to remove the existing structural brace/impact absorber/whatever it is


My money is on admin screw up or just ignoring it because who tows with a sedan?

Spoiler: answer

Europeans

 

[qwickshot]

Europeans tow more because every man and his dog doesn’t have a truck like in the US but only a very small proportion of drivers actually tow.

Up until recently you needed to take an additional test in the UK to tow anything over a small trailer up to 750kg.

The Model 3 isn’t actually a very good tow vehicle, it’s only rated for 1000kg which is nothing really.

Of those europeans that do regularly tow, it tends to be a caravan and there are only a handful on the market that are below 1000kg. Of those that are are those tiny bed pod things which most proper caravaners avoid because you can hardly stand up in them. I think there is only one ‘proper’ (but quite small) caravan from a mainstream manufacturer that is below 1000kg (Bailey D4-2).

In my mind it’s a cost saving measure and that very much falls into the tesla ethos (see USS).

Just think how many model 3’s they have shipped and even if they are saving as little as £100 per car not installing the cross member, that’s a lot of extra profit. Add on the savings from USS and you can see why they are the most profitable manufacturer in the west.

 

[Mrklaw]

but they don't install the crossmember on the Y either - they do that as part of the tow hitch install for £1200. So that wouldn't change for the 3.

 

[pdk42]

Back in the day, the UK was like the US - no tow bar homologation and no need to have the vehicle stickered for towing. After market bars were the norm and AFAIK, there was no major problem with failures. I don’t see that the new regs actually fix a problem that needed fixing.

But we are where we are…. A few years ago (before I got the Model 3) I was looking at a Golf R - but despite it being exactly the same in terms of body structure to the lesser Golfs, all of which are rated to tow 1.8 tonnes, VW hadn’t done the homologation work to authorise its use as a tow car. So, despite being able to buy a bar from VW, Bosal etc that would fit perfectly, it was illegal. So much for progress.

 

[doats1]

Only the Y has a rear beam that neesd to be removed where it looks like the 3 just has empty space.

A crash beam needs to be removed from the 3 as well so they're identical by the sounds of it.

I wouldn't be surprised if it was just an administrative cock-up when the cars were first imported. Maybe the Model 3 was fully homologated without the tow because of the different requirements in UK as opposed to USA ... then they subsequently applied for an add-on element tacked on just to cover the cars supplied with a tow package. I don't know how it works but I could envisage manufactures being allowed to do something like this but that such an extra wouldn't be possible to be done by private individuals so easily. [No evidence whatsoever ... just thoughts!]

I thought homologation was similar to getting a EPA or WLTP rating, as in it applied to the build rather than the specific unit. But maybe you're right.

 

[doats1]

Some high-level reading suggests that you could get personal type approval if there is a 'radical' change to the car. Whether adding a tow cross-member falls into that category is unclear. But even it did, it sounds like more money/effort than it's worth.

Vehicle approval

Type approval, individual (IVA), motorcycle single vehicle approval, voluntary approval, certificate of initial fitness, accessibility approval, fees, forms, replacement certificates

www.gov.uk

 

[noddy@teamterm]

Another data point. The Towbar is not currently offered by Tesla for the model 3 in Australia, however they continually advise it as "Coming soon". The vehicle meets the design requirements for towing, delivered with or without a towbar. Our M3's are built in Shanghai. I have an aftermarket towbar fitted that is certified and comes with compliance paperwork & a compliance decal for both the Towbar & the car. While purchased locally in Australia the Towbar actually shipped from the US due my location. It is faster to ship from the US than from Sydney.
While it is only certified for towing 1000Kg that is enough for my use. I tow a couple of trailers but the main one is a 900Kg Hash trailer which has barbeques, a couple of beer kegs lights etc, enough for a quite little drink for about 40 - 50 people. The car itself tows like a boss. It tows much better than the van it replaced. I could not tow a caravan but that is only because of the range reduction and that there is no fast charging infrastructure here where I am. (Well there is but they are 1600Klms apart)

 

[doats1]

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...

...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.

 

[Mr H]

but they don't install the crossmember on the Y either - they do that as part of the tow hitch install for £1200. So that wouldn't change for the 3.

Yes they do - i retrofitted an aftermarket tow bar and the crossmember was there. It is removed and then the tow bar fitted and then replaced over the top.

 

[doats1]

Yes they do - i retrofitted an aftermarket tow bar and the crossmember was there. It is removed and then the tow bar fitted and then replaced over the top.

I think what you removed was the crash beam, not the the tow bar cross-member. I had to do the same for my retrofit, but with the OEM tow bar you can't refit the crash beam on the 3 or Y.

 

[Adopado]

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.

What happened to Slip Start mode? There doesn’t appear to be a switch.

 

[rotarypower101]

I think what you removed was the crash beam, not the the tow bar cross-member. I had to do the same for my retrofit, but with the OEM tow bar you can't refit the crash beam on the 3 or Y.

Did you consider a aftermarket towbar/hitch to be able to retain the crash bar?

Does the crash bar serve any purpose beyond a structural crumpling element ? Several other vehicles I have utilized the crash structure as a element to help the flexible bumper retain a consistent profile/contour over time as the material tends to yield and sag over time.

Is the bumper skin completely independent of the crash structure, just for reference?



Still looking for a Model 3 hitch that has a vertically oriented square 2 inch "hidden" receiver.
Possible anyone has found a production hitch for the Model 3 with that configuration specifically avalible anywhere?

 

[Adopado]

Did you consider a aftermarket towbar/hitch to be able to retain the crash bar?

Does the crash bar serve any purpose beyond a structural crumpling element ? Several other vehicles I have utilized the crash structure as a element to help the flexible bumper retain a consistent profile/contour over time as the material tends to yield and sag over time.

Is the bumper skin completely independent of the crash structure, just for reference?



Still looking for a Model 3 hitch that has a vertically oriented square 2 inch "hidden" receiver.
Possible anyone has found a production hitch for the Model 3 with that configuration specifically avalible anywhere?

You are in UK/Ireland section of the forum. We have a different tow arrangement here.

 

[doats1]

What happened to Slip Start mode? There doesn’t appear to be a switch.

It's there but greyed out while Trailer Mode is active. Must be the image compression making it super faint.

Did you consider a aftermarket towbar/hitch to be able to retain the crash bar?

Very briefly, but I came to the uninformed conclusion that the OEM cross-member was probably manufactured to retain the structural integrity similar to the crash beam. I could be wrong though. I also found that aftermarket hitches that offered electrics had intrusive wiring setups, and I wasn't willing to splice anything.

Does the crash bar serve any purpose beyond a structural crumpling element ? Several other vehicles I have utilized the crash structure as a element to help the flexible bumper retain a consistent profile/contour over time as the material tends to yield and sag over time.

I've never known a bumper to sag over time so can't speak to this point.

Is the bumper skin completely independent of the crash structure, just for reference?

Yes, the bumper comes away from the beam with no direct attachment to it.

Possible anyone has found a production hitch for the Model 3 with that configuration specifically avalible anywhere?

Not in the UK I don't think. Options are very limited here due to regulatory restrictions.

 

[Mrklaw]

Yes they do - i retrofitted an aftermarket tow bar and the crossmember was there. It is removed and then the tow bar fitted and then replaced over the top.

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

 

[Adopado]

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

A tow ball that swings out automatically would be great.

 

[Mr H]

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

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'.

 

[doats1]

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'.

Some aftermarket kits allow you to fit the original crash beam back in again. But if you fit an OEM kit, the beam cannot be refitted. This is based on the actual Tesla service documentation and the fact that I fitted an OEM kit.

Both the 3 and Y OEM hitches bolt on the same way according to service docs. I doubt there is extra strengthening on the 3 because it’s legal to retrofit and tow on aftermarket hitches in the US.