[cduzz]

I think by keyed it isn't just "can't be plugged in upside down" but also "can't be plugged into the other plug that's basically the same but connects to some other subsystem."

Ideally a system like this would let you select some per-subsystem physical lockout mechanism.

[themaninthedark]

That level of keying would be done at the harness/electrical engineer level. You shouldn't put two same plug ends at one termination site.

You really couldn't control it at plug or part level.

[theamk]

It has to be both.

The plug manufacturer has to provide many, many keying options (say for a 2-pin plug, one might have variants 2A, 2B, etc... which explicitly cannot mate with each other)

An engineer designing the car has to ensure all plugs with same keying options are interchangeable (2A is for power supply; 2B for door switch; etc...)

If the plug manufacturer does not provide enough keying options, this will be pretty hard to during design time.

[themaninthedark]

You are generally not using just one plug style on a harness so most of the control is at the engineer level.

Unless you are a big player, what plugs you are using boils down to what receptacle the component that you want to attach to use.

[taneq]

Have they said there isn’t a mechanism for individually keying connectors? There might be something optional, even if it’s just blanking pins.

[numpad0]

Connectors with distinct shapes and sizes are usually used. If it feels like it could go in then it's the right one, and if it goes in it easily seats fully and never comes out without a tool. Wrong connectors don't even feel like they could go into wrong locations.

Cars using whole bunch of different connectors relying on whole bunch of suppliers is feature-not-bug situation. It is optimal for large scale volume production; work will be more distributed, SPoF will be more localized, etc. Standardized connectors with trivial visual differences and/or field configurable keying is a suboptimal solution for car problem. Usually.

...is it a local minima for small scale production? Are they having issues with scale outs, and therefore seeking downward scalability?

[taneq]

I work in this space and 100% agree, in fact I have been on a bit of a crusade to get the mechanical guys to stop designing parts that are rotationally symmetric for this exact reason. Letting a set of three parts be installed 17 different ways isn’t “keeping our options open” it’s “fucking up maintainers.” Each part should fit exactly one obvious place. Each connector should plug in at exactly one obvious place. The only exception is when it doesn’t matter where the part goes, which is approximately never.

That said, sometimes there are cases where an entirely new connector style isn’t warranted, and that’s where you use blanking pins or adjustable keyways or whatever.