Steyr 12M18 service manual?

I agree with Greg. My 16’ Unicat is from the last generation, lots of electronics but not interlinked. No failure in 12 yr/100k mi except 1 out of 2 Sterling battery to battery chargers. I assume that they provide wiring diagrams and component manuals. If so things are easy.
It’s ironic that you have an advanced electronic camper albeit with lots of redundancy and a totally optimized non-electronic chassis. No chance for electronics failure there!
I had the good luck to buy a chassis (the last year) that runs on high sulfur diesel and easily disconnected EGR.
No problem with the multiple computers but only with the “HD” alternator which I eventually replaced with a 28si 200A Delco. One of the biggest advantages of the computers is the automatic shifting 8 spd trans, easy on my mangled right hand and great in city traffic. It takes 3 interacting computers to run it but I have spares and there is a manual backup.
Don’t be afraid of electronics when the system is well designed and has quality components, which I think applies to Bliss.
Congrats on the Steyr!!! I was on the fence 2yrs ago on either the 12M18 or some type of SBU Unimog for a simple build-out camper. I finally decided on the latter due to parts availability...especially here in the states. We'll have to get together sometime for a beer. The wife works bi-coastal in Santa Cruz/St Augustine so I travel with sometimes...projects permitting. Try the guys over @ for a service manual. Great bunch of guys and are Steyr fanatics. Good luck.