So this is the wiring post.
When I removed the original wiring, I couldn't make sense of it. It was a mess, and being somewhat OCD about these things, I needed to organize it. And hey - it's a basically a kitcar, how hard can it be?
The wiring was actually not that old, but it was already modified somewhat, and clearly belonged to a much newer car, as it had a lot of extra connections (like fog lights, electronic ignition, etc). But it lacked some of the wires for the functions I was planning. First thing I did, I mapped the whole thing. It was winter and I was very bored.
It must've taken me days... What I discovered, was that a lot of functions are wired directly and without relays or even unfused. The only relays there were actually for horn, indicator blinker, indicator relay and lights relay. For example the fuel pump was straight from the ignition, and caused some corrosion on the connector already (lots of amps there). So I added relays for the fuel pump, for the radiator fan and for any accessories I may later add (intercom, phone charger, navigator charger, like that). And fuses for everything.
What helped a lot, was that British wiring is standardized, everything is colour coded
. Not that colours made a lot sense (brown for positive! argh). Then there were tricks with instruments, some of which need their own voltage stabilizer. Wiring for the lights was strange. Left and right side were wired separately - which is understandable (better to have one side to fail and whole front or rear), but the wires went from the dash to the front light, then BACK the same route all the way to the rear. Even if the goal is to avoid splits in the middle of the harness, it's a much shorter route to separate them under the dash rather than put the front and the rear in series. Which is what I did.
But anyway, next I made a new plan, with functions separated in blocks.
I had a few unused switches on the dash, I used one of them for manual override of the cooling fan and another one to switch accessories on and off. Also the oil temp and pressure I mentioned earlier. I also added some wiring for the inertia switch. It's a mechanical switch which breaks the connection to the fuel pump if it experiences significant vertical g, if the car rolls, for example. I'll be putting it under the dash, so it can be reached and re-armed manually if I drive over a particularly large pothole and need to restart the engine, for example.
With plan completed I could start doing the actual wiring. That was spring by now. My living room looked like this for a month or so
I removed a ton of wires in the end, the new wiring is much simpler, more logical, and most importantly - I know where all the shit goes
Test fitting to cut under-dash portion to length:
Fitting to the car
Then there was a problem of relays and fuses - where to put them? In original wiring they use these 4-way interlocking relay sockets, which were bolted directly to the vertical plate ("firewall"). I couldn't find a single supplier of these sockets anymore, so I decided to go with completely different set, and got a bunch of these
from VWC. There's a relay and 3 fuses in one, and they interlock. I managed to fit everything into 7 units.
when mounting it all to the vertical plate, I wanted to have relays and fuses facing the interior, for easy accessibility. So my patented solution was to make a shelf from a metal plate which I bolted to the vertical wall. The sockets sit on this shelf, and behind them is a few cm of room for the wires. Like this:
It's a view from the passenger lap, more or less.
And this is the view from the other side (vertical wall removed for now):
And now everything wrapped with some loom-tape (no-glue sticky PVC tape - excellent stuff for wiring).
Another curious observation, look at the dash photo in one previous post, all the switches are in off position, but they are switched up! One of those little differences between UK and the world
Apparently light switches in apartments follow the same rule, in UK up=off, down=on, and the opposite everywhere else. I couldn't reverse them here, some of the switches aren't toggles (like the washer), and I didn't want to have the icons upside down. But the long-handle toggle switches on the right side of the steering wheel (high beam switcher and flasher) I did reverse, switching them down to turn on just doesn't feel right.