1980 Austin Princess mild custom - 1951 Lanchester LD10

I'm with Blackpopracing, I'd be expecting a diagram, colour code and pinout for a custom made wiring harness. Buy a universal kit car harness and you'll get a diagram with it. Different if your buying from the OEM, wouldn't expect one then, but you know it would be a direct replacement.
I've made a couple of custom wiring harness sections for friends (i.e free other than material) they both got diagrams with colour codes and pinouts.
e.g.
Linky and Linky 2

You suspect correctly. The most confusing thing is that there's something like half a dozen separate sections and no indication of which ones join to which others, or where. The wire colours help to a degree of course, but none of it has the shape memory of a harness that's been removed from a car.

They clearly have a diagram they work from to build the harness and a single sheet simplified print out just as a guide for what you've got in your hand would really help speed up instalation since you wouldn't be guessing at anything. It's one of those things that the more I've thought about it since BPR raised it, the more strange it seems that the basic courtesy of a couple of sheets of paper explaining the product has been omitted.

Until I get a reply I shan't know if the lack of paperwork is normal or not. It won't be a problem either way, I'm smart enough to be able to figure out where things go given enough time, wiring diagram or not, so it'll get done anyway.

This is the trouble when you have zero experience of doing a job, you don't always realise there's a question to ask until someone points out the answer to it.

They will have built it to a pattern. That might have been a factory original specification, because they were in business making OEM looms back in the day, or it might have been an original loom that was laid out and copied. It wouldn’t have been made to a conventional wiring diagram though, no more than the London Underground was dug to match the schematic map we’re all familiar with.

I've never seen a original spec loom come with a wiring diagram, it's assumed you have the manual with it in, they may not even have a wiring diagram most loom drawings specify cable type, branch lengths and connectors etc but not what they are connected too. A trick if the car still has the original loom is to snip all the connectors off with an inch or so of cable leaving them on the switches etc, then when you fit the new loom pull off one at a time and replace with the matching colour. In this case there doesn't look enough of the original wiring though.

^^^ ha-ha! I think my ignition circuit alone is more complicated than that, lol!

It's not so much the lack of wiring diagram that's been the issue, as demonstrated above wiring diagrams for this car are surprisingly easy to get hold of and it's a simple harness. It's more the lack of any labelling on the new parts that's the issue. Just knowing which is the front bit and which is the back bit speeds it all up, for example, since you're not having to test and check you can just pick it up and go "oh right, headlighty bit".

Next chance I get I've got to get the car up in the air to have another look for the wiring route. It's supposed to run along the chassis to go from front to back but when I've looked I've not been able to find it. I suspect the old wiring is probably so dirty I've not been able to see it while I've been under the car, or it's been rerouted due to repairs (less likely since all the other repairs are bright colours and easy to see). I've had various suggestions on the route, most recently that it goes along the chassis, over the rear cross member and up the side of the petrol tank, fairly well hidden if you're not viewing it from the right angle. I couldn't find any wiring in the cabin that seemed to head up into the roof so it's probably that the semaphores have a tail coming up the B pillar from the chassis rather than running over the top of the doors from the dashboard.

There's not a lot of video and photographic info on how these cars are put together so we're still flying a bit blind. Hopefully our fumbling about in the dark is going to help other people with their projects, certainly the Lanchester has had more attention on its various homes online than we really expected so we must be doing something right/entertaining.


And yes, daft as a sweeping implement, peculiar as a container of amphibians, that's me.

Remember this?


Had some time after work today to quickly hook it up to a power source to see what it does. The unit buzzes, which suggests the vibrator is vibrating, and the buzz quietens down as everything warms up. One tube I could see glowing through the case vent (I didn't take the case off for testing, I will for next time) so power is getting to at least one tube. However, with no aerial hooked up and not knowing what else does and doesn't work, that's as far as I got. No smoke, no horrible smells, nothing getting hot so it will probably be able to be revived. The selector doesn't illuminate either, but that could be a blown bulb or attention to the wiring required, we'll find out when I dig deeper into it.

I feel a bit more confident digging into it now at any rate.

Noted. All of the old wax capacitors are going to be replaced, it's still running what are presumably the originals from 1948 and while there was no sign of leaks or bulges when I was doing the cleaning, there might be now. Only had the unit running for a few minutes, didn't push my luck. Next step is to acquire all the new bits its likely to need and get on with replacing things before testing again.

In other electrical news, today the last of the engine bay wiring was removed. The repair work done in the past has muddied things a lot, we need to go through and work out what's actually been done so we can understand it a bit better. The best news is we've finally found the route the wiring takes to the back of the car. The reason we couldn't find the wiring before is that it is quite well hidden unless you know where you're looking. With all the new stuff out of the engine bay we could actually see where the original wiring disappears into a boxed section of the chassis and could then find it underneath the car where it reappears in an open section of the chassis and runs to the back of the car. This probably means the wiring branches off at the B pillar on the driver's side for the semaphore, goes up to the interior light (which has never worked while we've had the car) and down to the other semaphore. In theory, we should be able to attach string or similar to the passenger side semaphore wiring and the interior light wiring to pull the old wires through and then feed the new wires back in without disturbing the headlining at all.

We've also found more and more problems with the old wiring as we've removed it from the car. It really does seem like it's the failing wiring that took the car off the road more than anything else, clearly someone has gone to a lot of effort to keep things going, it just wasn't enough as the old wiring continued to disintegrate.

My advice would be to disregard the original loom, and the recent additions, in all but the most basic of guidelines as to layout; and even then only for the stuff that’s definitely in its original location.

Your new loom will have all the right colours and connectors to fit with what should be on the car. Identify which bits of the new loom go where first, for instance blue/white and blue red go to the headlights, or the dipswitch, and it should be obvious which end is which. Once you’ve got the basics of what bit of the new loom goes where, you can start fitting it.

It’s daunting, yes, but once you’ve done this one you’ll wonder why anyone thinks it’s difficult.

And, if you really do get stuck, I’ll come up and help.