Sooo, I think I narrowed my electrical worries down a bit, maybe even to the root cause but that's to early to tell for now.
Got a new battery today, and then did some other testing. Everything is working, including the interior lights. Exceptions are: horns, the non-constant beam, coil and wiper/washer. Intermittent failures on oil and ignition warning lights when the ignition is on. I traced all those things to fuse number 3. And that fuse continues on to, I could have guessed, the starter motor.
I did check the ignition lock wiring, it is fine and properly connected. I assume the whole wiring loom is fine was well, besides the mysteriously missing other end of the black-pink wire from the parking break sensor and two black-white ones for a brake system warning light I now assume are for a different VIN. That leaves as the only place where wires can be crossed and circuits broken, the starter motor. And there I seriously found cobled together wires that started with color one, had something else for a bunch of cm and went on to a different color. And I do have a broken contact there as well.
Until the new starter motor shows up, I'll some mechanical things: window winders, the passenger door lock, the right front inner wing to chassis mount, poperly installing the front lights and grill. And maybe I manage to chase down that parking brake sensor cable. If not, well, I have to pull some wires for the transmission temp sensor. I can as well put in one for the parking braking sensor while I'm at it.
And the second electrical circuit from the secind battery: two 12V plugs where the radio normally goes, two where the center coin tray is and two into the trunk.
October is approaching fast so, I need to speed things up a bit!
