Comment by kube-system
1 day ago
> Turns out that actual cars don’t have individual cables. Instead they have these big “looms”, which bundle many cables from a nearby area into a single harness. This is the reason why I could not find the individual cable earlier. They simply don’t manufacture it.
I was really surprised to read this at the end of the article -- how could someone be this deep into a project of this depth and not realize this?! Not only because all cars (...er... all vehicles) are wired this way, but also because the documentation they were referencing has plenty of detail to show this... there's even a whole picture of it (and to Tesla's credit they have amazing free docs): https://service.tesla.com/docs/Model3/ServiceManual/2024/en-...
> how could someone be this deep into a project of this depth and not realize this
I think this is a software guy who occasionally dips into hardware things (to hunt bugs).
That's what I figure -- but it was wild to read that after reading the part about component-level PCB repair lol
Yeh, it seems odd to have the cut off cables, the wiring information...and then to go and buy a loom rather than bodging a cable at that point.
Even if you know that cars consist of a single wiring harness, it's not implied that they aren't modular and the individual cables cannot be purchased separately.
Cars usually consist of multiple harnesses -- as it is in this case as well. The harnesses are the cables in a car. That is the part you can purchase because that is the part.
There's a list of them here: https://service.tesla.com/docs/Model3/ServiceManual/2024/en-...
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Why are you so hostile towards someone who's experiment with an interesting computer? What's wrong with you?
I was more fascinated that a new wiring harness was $80! I've easily spent $30-50 for a single VAG cable 1ft pigtail.
> and to Tesla's credit they have amazing free docs
Not to Tesla's credit, they had to be dragged kicking and screaming into it (primarily by Massachusetts) and their right to repair legislation through a solid chunk of malicious compliance:
1. When told that they had to have a site for people to order parts, Tesla put up a site that had every single item as "Call us", including the most simple of bolts. And when a few places called, "Sorry, that's not available to you".
2. The service manual was originally only available in a few locations in MA, and had strict conditions: you had to book in advance, there was a $100 fee per booking, and you could only view the manual on premises, and could not bring electronic devices into the room with you, just pen and paper.
The docs they have are great, and who knows how their attitude would have changed over time, but they absolutely didn't want you to have it, initially.
Tesla treated the service manual like congress treats certain recently surfaced files.
Wrong. They’ve always been open, even with their patents too. All free to use, no royalties
Confidently incorrect.
https://www.reddit.com/r/teslamotors/comments/utivlj/tesla_s...
> This used to cost $3187.50
https://driveteslacanada.ca/news/tesla-service-manuals-free-...
> The access story has been inconsistent over the years. Tesla has opened up free access to both the service manuals and diagnostic software in the past, but that was apparently a mistake, and loopholes were quickly closed.
https://www.teslaownersonline.com/threads/tesla-service-manu...
"Always ... all free to use". Not so much. And before that, even less available.
I will grant you for number 2, there seems to be some ambiguity - some people claimed it was only if you needed to actually use their diagnostic tools, because Tesla wouldn't sell them to anyone at the time (which is also in contradiction to your "everything you need, all free, always").
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I will say I’m surprised how far apart the two boxes are in the car. I guess they’re not where I thought. I would assume they’re both up near the dash.
The passenger side kick panel or behind the glove box are two very common places for vehicle computers -- some cars have them under the hood, which I always thought was a bad idea.
My RAM truck with the Cummins diesel engine has the engine computer mounted on the engine block. You'd think the heat and exposure to the elements would make that a bad idea, but I suppose Cummins knows what they're doing.
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If you'd like the cursed location for a vehicle computer, have the Smart fortwo's SAM. It's the fuse box!
It's also notorious for having awful solder connections and failing outright.
https://evilution.co.uk/mod/sam-unit-solder-repair.htm (and Aging Wheels: https://www.youtube.com/watch?v=n8AAleKR33Q)
> I was really surprised to read this at the end of the article -- how could someone be this deep into a project of this depth and not realize this?!
Usually, for most other vehicles, the connectors are either standardized (e.g. radios, ISO 10487 [1], high-current chargers by VG 96917) or the foundation plugs, sockets and re-pinning tools are readily available by the vehicle manufacturer or by aftermarket suppliers.
Tesla truly went out of their way to make the life of third parties (such as wire harness repair shops) more miserable here.
[1] https://de.wikipedia.org/wiki/ISO_10487
EVS have actually managed to reduce the number of wire bundles (mostly due to switching to Ethernet instead of CAN Bus)
How?
When canbus is already two wires, and by definition, is a bus, so you can just keep stringing those two wires to any module you need. I know Ethernet BUSes exist, but what advantage would those have to canbus then? They're both two-wire buses.
Tesla also went to a 48v wiring harness in some of their vehicles to allow them to power more equipment with less copper. It might be one reason why they use nonstandard connectors, so people don't attempt to hook 12v equipment to the system and also the higher voltages might require connectors rated for it.
Now they just have to take the next step and have everything in the vehicle running on PoE.
Software people tend to overestimate their knowledge of other disciplines, writing it off as "easy" or work beneath them. Being overpaid compared to your peers certainly doesn't help dispel this feeling. Some people have built entire careers around designing wire looms.
> Software people tend to overestimate their knowledge of other disciplines, writing it off as "easy" or work beneath them
You should see what happens when someone involved in the sciences, e.g. Chemistry, gets their hands on Claude Code.
What happens?
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Consider whether this is an uncharitable comment --- someone with little expertise in a discipline has made a rookie mistake and didn't realize that the wires weren't produced individually.
Professionals overestimating their knowledge is a very common thing!
Fair, but software engineers are especially known for this. There was an XKCD about it
https://xkcd.com/1831/
What a rancid comment. The first thing you can think of when seeing someone earnestly sharing their learning process, is to insult them of being vain.
Try working on a software project as a non-developer and see if you still respond so negatively to their sentiment. I can’t tell you how many times developers tried to arrogantly and dismissively explain design principles to me, as an experienced, degree-holding designer, because they skimmed a whole Tufte book at some point.
I was a developer for a decade before I went to school for design, so I’ve seen it from the other side. It’s not all bad: that overconfidence can lead people to tackle problems they’d abandon if they really understood the domain’s complexities. But often it presents like developers acting like their genius developer brain allows them to solve difficult problems in completely different fields with a few glib analogies and a few brief thought experiments.
He's right about the rest. We software people can definitely be annoying.
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There's a reason that John Salvatier's 'Reality Has A Surprising Amount of Detail' blog entry is so evergreen on this forum.
People tend to overestimate their knowledge of other disciplines.
I have worked with a LOT of PHD's in recent years. Their code leaves much to be desired.
It's called misplaced confidence and it isn't exclusive to software engineers. Doctors, engineers, presidents... The list goes on.
I don't know, I've had more non-technical people and trades try and mansplain bullshit they don't understand than tech people have.
I'm sure you're an expert, pro at everything.
I wasn’t criticizing them.
Yes I am. Thankyou for recognising that