Lotus Elan and Lotus Elan Plus 2 Forums

Dear Elan Wiring Experts,

I'm getting ready to take the plunge and purchase engine bay, interior, and trunk wiring harnesses for my '69 S4 DHC. I'll admit to more than a little trepidation, as electrical is not my wheelhouse, but with the wiring in my Elan being a combination of 50-year-old stuff and a bunch of non-standard bodges, I believe I'm better off just starting over from scratch.

I'm purchasing my wiring harnesses from British Wiring. They offer two "Main" harnesses for the S4: the Main Harness with Alternator:

http://www.britishwiring.com/Lotus-Elan ... -p/832.htm

and the Main Harness with Generator:

http://www.britishwiring.com/Lotus-Elan ... -p/822.htm

My car has a modern, Japanese (I believe, Mitsubishi) alternator installed by the previous owner. I still have the generator control box on the firewall, but it has been bypassed, pursuant, I am told, to the instructions provided by RD Enterprises (the source of the alternator).

Clearly, my current wiring harness is (largely) the one originally provided with the generator-equipped Elan.

So, which British Wiring harness do you recommend I purchase?

I have emailed British Wiring this question but have, so far, received no response.

Thanks in advance for your thoughts on what, I am certain, is only the first of many electrical questions!

-John

When I did this on my '66 Elan, I purchased the Generator harness, extra wire of the appropriate colors, harness tape, and bullet adaptors. I added or modified the harness for the alternator and added extra wiring for the electric fuel pump and electric fans. It looks like a factory harness with none of the bodges that could have ended up in the car.

It wasn't hard to add the extra wires and re-tape the harness where needed, It was just time-consuming. The most difficult part of swapping the harness was figuring out where everything goes. My original harness was so chopped up that I couldn't use it as a template.

Looking back through my blog post, I also tied them back any unused original wires and wrapped them inside the harness just in case I, or a future owner, ever need them.

Thanks, Jim. You clearly have have considerably more experience (and ability) with automotive wiring than I. I really need to select the product that will require the absolute least possible additional work. I realize that may end up being your approach, but I'm hoping i can avoid the amount of splicing and modifying you describe.

Has anyone out there installed the British Wirlng "alternator" harness into a car converted from generator to alternator?

I also have a 69 S4 DHC, Federal version. Presumably the same as your car.

I purchased my wiring harnesses with the generator wiring, realizing that the alternator version was set up for the early Lucas alternator and wouldn't have the right connectors for my modern Japanese alternator any way. Then, just used the wires as specified by the alternator instructions and discarded the extra ones on the loom for the generator.

Not a big deal.

There are a couple of other nuances:

1. Headlight wiring (Black-Red wire), and the switches, that are different for Federal cars. Not sure the harnesses provided by British Wire have been modified for this. Typically, all of the harnesses are made by Autosparks. If you buy them out of the UK - you have to make the Federal modifications. Not sure if they make special versions for the Federal cars that British Wire then resells. I noted that the catalog numbers were the exactly the same from Autosparks and British Wire.
2. A grounding wire for the instruments, not included on the new loom.

If you get into a bind, ask for help. I'm in California.

Fantastic. Many thanks. Two more questions:

British wiring lists three wiring harnesses for the S4: The Main harness, the Body harness, and the Dash harness. First, do I need all three? Second, I see no trunk harness - can I assume the Body harness takes care of the trunk wiring?

The main harness (822) is for the engine bay. The dash harness (823) is for the dash. The body harness (824) goes to the rear. Whether you need all three is up to you. I bought all three but resold the rear one since my wiring there was fine.

https://www.autosparks.co.uk/finder

I did my S4 FHC several years ago. I used all three harnesses, alternator version. The harnesses were perfect, no glitches.
Get the wiring diagram for your car and get it blown up so you can see it well. The Lucas wiring scheme is brilliant. It will seem like a colossal mess at first but just plug away and you will really know your car when you are done. Make sure your grounds are good, and if you have to, add extensions to some of the dash wires so there is enough slack so it can be pulled easily. The first time you put it in probably won't be the last.

Thank you. That’s exactly what I needed to hear! I’m ordering them tomorrow. I’ll keep everyone posted as this phase of my project moves forward.

Cheers!

-John

Just a small question did the federal Elans have a Hazard Warning Switch. On my UK Sprint there is no Hazard Warning Switch.
Alan

alan.barker wrote:Just a small question did the federal Elans have a Hazard Warning Switch. On my UK Sprint there is no Hazard Warning Switch.
Alan

Alan, Federal Elan Sprints certainly have Hazard Warning switches.

jbeach wrote:Thank you. That’s exactly what I needed to hear! I’m ordering them tomorrow. I’ll keep everyone posted as this phase of my project moves forward.

Cheers!

-John

..

John a couple of warnings

1. The US wiring is different than for the rest of the world. Do you have red/orange rear lights or single red bulb? If the latter you have the DB10 relay box under the dash & your wiring is quite different. As Alan has mentioned Federal cars have hazard lights whereas the UK does not

2. Looks like British Wiring use Bullets to connect between the main (engine bay) harness & dashharness. Your car probably has a multi-way connector between the two. As you are changing both not that big a deal...

What is wrong with your original harness? Is it repairable? I removed about 20 hacks from mine last winter rather than replace

If you're still going to replace your harnesses I would be interested in recovering the multi-way connector.

Just a few caveats. The Federal S4 wiring (at least on my original 1969) differs from the later Federal Sprint:

1. The hazard switch is a slide switch , semi hidden on a small bracket located above the handbrake pull. Along with a push button to check the brake fail light. Factory original. The Sprint has a rocker hazard switch in the middle of the lower dash between the headlight and fan switches.
2. The main and dash looms are indeed connected by bullets, not a multi-plug like later cars.
3. I have the red-orange taillight lenses, but they were originally solid red. But the tail light inners have separate bulbs, as noted, for brakes/night (dual filament) and turn indicators. Since I didn’t change my rear loom I didn’t run into any compatibility issues. I don’t have a DB10 relay for the hazards under the dash either. Different cylindrical flasher unit is used.

There are differences between the S4 and Sprint, and different harnesses.

jbeach wrote:Thanks, Jim. You clearly have have considerably more experience (and ability) with automotive wiring than I.

I didn't before I started! As someone else said, get the wiring diagram and have it blown up as big as you can. I took notes on mine and still have it on my shelf as a reference.

You will be fine. I replaced all the wiring in the Plus 2 and had never done anything of that magnitude before. Great winter/spring project.

Feel free to ask anything as you get started. There are several folks here that are really knowledgeable. Make sure you keep mentioning your year and model in any questions though; as you are well aware it gets confusing with running changes.

Stu

Good luck with the Wiring at least it's colour coded.
On my 1978 TVR 3000S ALL the WIRES are BLACK with silly little Sleeves at the ends. Almost impossible to read and if you're lucky you can roll them inside out to see what the original colour was without them falling apart
For sure if you need to add to the new Loom make sure you use the correct colour with the correct tracer.
Alan