Connectors - HSD, na ha ha hot 'Fakra'
What it Is, and What it Ain't
The cable between the ICU and MCU is ethernet, and that it has HSD connectors. (High-Speed, Differential signalling) - NOT "fakra" -- you get a slap if you say "fakra" which are co-ax not ethernet.
These connectors are -keyed- and the HSD connectors throughout the car are keyed -differently-, type A, B, C, etc.
The Skeleton Key
BUT there is a 'skeleton' connector which will plug in to any of them, type Z. The best way to connect to any of these is to buy a Z-type HSD cable, male to female, ~1 to 2 meter on Ebay, cut it, and crimp RJ45 connectors to the cut ends. Maybe someone is selling premade cables now, IDK.
Amusingly though, if you use a quality shielded RJ45 connector like Ubiquiti's, the jacketed wires from the cable will not fit into the darned RJ45 slots. So I had to carefully shave jacketing off enough to slip them in, using a high quality Klein wire stripper which was very sharp. (Home Despot) I always first inject silicone grease into the RJ45 to make the connection gas-tight. ('dielectric grease' - auto parts store)
Stick one HSD in the MCU, and the other into the ICU's HSD connector. Flange in your switch.
Carl A. Cook