| ▲ | kube-system 11 hours 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-... |
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| ▲ | entropie 10 hours ago | parent | next [-] |
| > 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). |
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| ▲ | kube-system 10 hours ago | parent | next [-] | | That's what I figure -- but it was wild to read that after reading the part about component-level PCB repair lol | |
| ▲ | trebligdivad 9 hours ago | parent | prev [-] | | 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. |
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| ▲ | spuz 10 hours ago | parent | prev | next [-] |
| 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. |
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| ▲ | FireBeyond 9 hours ago | parent | prev | next [-] |
| > 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. |
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| ▲ | cluckindan 9 hours ago | parent | next [-] | | Tesla treated the service manual like congress treats certain recently surfaced files. | |
| ▲ | creantum 8 hours ago | parent | prev [-] | | Wrong. They’ve always been open, even with their patents too. All free to use, no royalties | | |
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| ▲ | mschuster91 9 hours ago | parent | prev | next [-] |
| > 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 |
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| ▲ | MBCook 10 hours ago | parent | prev | next [-] |
| 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. |
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| ▲ | kube-system 10 hours ago | parent [-] | | 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. | | |
| ▲ | msisk6 9 hours ago | parent | next [-] | | 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. | | |
| ▲ | phil21 8 hours ago | parent | next [-] | | My car has it under the passenger seat. Sounds alright until you realize after spilling a bunch of flower vases in the trunk (hatchback) that the computer has literally no case on it and immediately shorts out while driving. Or a passenger spills a drink in the rear seat cup holder. There is now a recall notice to pull the back seat out to install a $5 plastic cover over the thing. And yep, it’s the main computer for the car which controls the electronic transmission etc. Immediate full on engine-shuts-off at speed on the freeway and you require a flatbed to tow it away level of broken. I’m sure the engine ECU is in the engine bay, but holy hell what a surprise! | | |
| ▲ | bdunks 8 hours ago | parent [-] | | I had a car with an all wheel drive computer in a similar spot in the late 2000s. I had a small crack in the rubber seal around my sunroof from parking outside in the elements. When it rained, water seeped in, made its way down the a-pillar, pooled under the seat, and fried the computer. Expensive fix but I was able to drive it to the shop. |
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| ▲ | kube-system 9 hours ago | parent | prev | next [-] | | Hehe I was thinking about FCA/Stellantis vehicles when I wrote that. I know it works and there are components made to work in that environment but it always felt intuitively wrong to me. Especially when the other side of the firewall is a much better environment and not far away | | |
| ▲ | yearolinuxdsktp 9 hours ago | parent [-] | | It’s because when placed inside the engine bay, the large wiring harness is shorter, which is not only cheaper, but also shorter wiring helps with the consistency of electrical timing and reduces noise. |
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| ▲ | cuvinny 8 hours ago | parent | prev | next [-] | | Could be because they sale crate engines. | |
| ▲ | yearolinuxdsktp 9 hours ago | parent | prev [-] | | Yes they do. They can tolerate engine bay heat, but not exhaust heat. They are usually shielded from getting soaked. Some Mazdas put the metal-cased engine computer in a plastic air box that feeds cold air from the front, to help ensure the engine computer stays cool enough. In general, I believe the cooling airflow from the frontal air and the cooling fans keeps engine bay in check. For example, this is the board that’s used in Mazda CX-5 2017+ engine computers (mfr Denso), it lists max temperature range of +150C: https://www.renesas.com/en/document/mah/rh850e1l-users-manua... | | |
| ▲ | msisk6 8 hours ago | parent [-] | | Yeah, on the Cummins the ECU is mounted on the intake side of the engine away from the exhaust and turbo and toward the front right under the fuel injection pump so it gets lots of cooling air. This thread is interesting to me 'cause I'm also a software guy and recently took a job dealing with building fighter jets and the amount of engineering going into the wiring and computers on those things is insane. It's been a very interesting learning experience. |
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| ▲ | kotaKat 9 hours ago | parent | prev [-] | | 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) |
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| ▲ | Onavo 9 hours ago | parent | prev | next [-] |
| EVS have actually managed to reduce the number of wire bundles (mostly due to switching to Ethernet instead of CAN Bus) |
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| ▲ | jandrese 7 hours ago | parent [-] | | 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. |
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| ▲ | longislandguido 10 hours ago | parent | prev | next [-] |
| 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. |
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| ▲ | acuozzo 9 hours ago | parent | next [-] | | > 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. | | |
| ▲ | juleiie 9 hours ago | parent [-] | | What happens? | | |
| ▲ | incrediblylarge 9 hours ago | parent | next [-] | | A professional scientist I know (tenured, professor) recruited me to set up a backtesting framework for a predictive finance model. When the results were not as they expected (this person does not work in finance and never has), they asked to see the code, then told me that claude had found a problem with the way some of the calculations were done (there was actually no problem), supplied the claude comments, and told me to change the code to match what they thought was correct. I did it anyway. Had they had more expertise in the domain (finance), they likely would have been able to leverage claude as a tool rather than inadvertently pursuing a very stupid mistake. Domain experts tend to doubt their ability to excel in other domains which is amplified by LLMs. | | |
| ▲ | Reason077 7 hours ago | parent | next [-] | | This sounds rather similar to the form of scientific fraud where you first create a conclusion, then invent/manipulate the data until it supports your conclusion. | |
| ▲ | zer00eyz 8 hours ago | parent | prev [-] | | I work with a bunch of PHD's and have been since before ai coding. Their code is aways terrible, and they constantly think it's good. The exercise is always the same: explain the math to me, like I'm 5, then we profile it and see what is faster. Oddly Claude Code, integrated into their IDE's has made this situation happen much less. I never want to work in a place again where the fun way to start the Monday meeting is a "math problem". PS: Don't even get me started on their SQL. |
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| ▲ | acuozzo 5 hours ago | parent | prev [-] | | They suddenly act as if Claude has awarded them with a second PhD in CS. Now they know everything and everything you tell them gets filtered through Claude. It's like "software dude thinks he can do hardware", but on steroids. They don't know what they don't know and they think they have a panacea in their hands. Don't you know? Software is beneath them and the fiddly bits are just standing in the way of them getting their BigImportantWork™ done. |
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| ▲ | desmondwillow 8 hours ago | parent | prev | next [-] | | 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! | | | |
| ▲ | kvuj 8 hours ago | parent | prev | next [-] | | 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. | | |
| ▲ | DrewADesign 8 hours ago | parent | next [-] | | 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. | |
| ▲ | rpmisms 8 hours ago | parent | prev [-] | | He's right about the rest. We software people can definitely be annoying. | | |
| ▲ | OccamsMirror 8 hours ago | parent [-] | | All people are annoying. It's still mean spirited in this instance. The author is likely reading all of these comments. |
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| ▲ | EA-3167 9 hours ago | parent | prev | next [-] | | There's a reason that John Salvatier's 'Reality Has A Surprising Amount of Detail' blog entry is so evergreen on this forum. | |
| ▲ | SecretDreams 8 hours ago | parent | prev | next [-] | | It's called misplaced confidence and it isn't exclusive to software engineers. Doctors, engineers, presidents... The list goes on. | |
| ▲ | zer00eyz 8 hours ago | parent | prev | next [-] | | 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. | |
| ▲ | gedy 8 hours ago | parent | prev [-] | | 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. |
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| ▲ | moomoo11 9 hours ago | parent | prev [-] |
| I'm sure you're an expert, pro at everything. |
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