Lotus Elan

New wiring diagram for peer review

PostPost by: Bushwacker » Wed Feb 24, 2021 3:44 pm

My files were created in Photoshop, not some CAD program.
It seems that the maximum file size to upload is 2MB.
Even a scaled down PDF file is 3MB.
PM me if you want me to email you a larger file.


Thanks,
Eric
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PostPost by: Elanman68 » Wed Feb 24, 2021 5:23 pm

Eric,

Thank you, have sent you a PM.
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PostPost by: Elanman68 » Wed Feb 24, 2021 5:31 pm

billwill and h20hamelan,

Thanks for your helpful suggestions. I can open the image and save it on my iPad and once there can expand it but it loses sufficient definition to be illegible beyond a certain point. Eric has kindly offered to e mail me a copy. I currently have the entire drive train out of my car as taking the opportunity to do a number of long aspirational jobs once I needed to replace the clutch release bearing. One of the jobs is an engine bay tidy, including the rather messy wiring hence my interest.
Last edited by Elanman68 on Thu Feb 25, 2021 10:24 am, edited 2 times in total.
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PostPost by: Bud English » Wed Feb 24, 2021 6:28 pm

I know that this doesn't help you much at this point, but anyone else wanting to replicate a diagram or create a new diagram, I would suggest using software made for this purpose. I use Scheme-it, a free to use, on line electronics program from DigiKey. https://www.smartdraw.com/wiring-diagram/

If I had found Smart Draw before I started, I would have used it instead. It's not free but the ease to create automotive diagrams makes it worth the monthly cost, at least it would for me. https://www.smartdraw.com/wiring-diagram/

Being able to export diagrams as a PDF is most useful. Here's an in progress example from Scheme-it.
Attachments
Lights Page 2, 02-09-21.pdf
(75.06 KiB) Downloaded 33 times
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PostPost by: Andy8421 » Thu Feb 25, 2021 12:07 pm

Eric,

I had a look at your mark 2 diagram. All looks good, though the hazard wiring is still missing.

Andy.
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PostPost by: Bushwacker » Thu Feb 25, 2021 4:00 pm

I have added the missing wiring to the hazard lighting circuit and cleaned up the connection from the dizzy to the coil.
Sorry for all the versions. It is a work in progress, as they say.

Cheers,
Eric
Attachments
Lotus Elan Wiring Diagram 36-5357 v022521.jpg and
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PostPost by: Bushwacker » Fri Feb 26, 2021 11:16 pm

As Monty Python would say: "And now for something completely different".

Here is a different style of diagram which some may find easier to look at and think through. Not concerned about where items are located in the car, just how one thing connects to another.

Have a look at this and let me know what you think of this.

Thanks,
Eric

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PostPost by: billwill » Sat Feb 27, 2021 12:06 pm

Much better for me at least, because you can follow (usually) what is happening.

Though personally I would show what the inside connections of the various switches are to be able to "follow the electrons".

And you left out the actual starter motor.


Wiring diagrams which try to follow the layout of the actual wiring loom are unnecessary (ideal for the bloke actually building a loom on pegs on a board) but difficult to read for anyone else.. All you really need to know are where the ends of the cable are and (usually) what colour(s) are the cable.

~~~~~~

Later: Oh I see that you meant that your starter motor has been replaced by one with a built on solenoid.

I don't understand your Horn circuit, you show only one earth and that is through the horn button, so the HEAVY horn current would seem to go through the horn button, making the relay just a nuisance instead of a help.
Bill Williams

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PostPost by: Bushwacker » Sun Feb 28, 2021 3:46 am

Hello Bill,

Thanks for catching the problem with the horn circuit. I went back to my reference book ( Classic British Car Electrical Systems by Rick Astley) and found the correct circuit layout for the horns. They suggest running a separate wire from the fuse to energize the coil of the relay with the push switch on the other end of the coil.
The power comes through the horns and enters the relay then exits to ground. Check out the modification to my diagram. I also realized that I had forgotten to ground the two headlight relays the same way, so that is now fixed as well.

Thanks again for the input.

Eric

Lotus Elan wiring diagram pictoral style v2.pdf
(1.15 MiB) Downloaded 19 times
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PostPost by: HCA » Sun Feb 28, 2021 10:33 am

billwill wrote:Wiring diagrams which try to follow the layout of the actual wiring loom are unnecessary (ideal for the bloke actually building a loom on pegs on a board) but difficult to read for anyone else.. All you really need to know are where the ends of the cable are and (usually) what colour(s) are the cable.

.


Very true indeed! Many get caught up in the actual diagram that only ends in confusion. I have rewired many older cars and use two central points - a fused and unfused block - from where I take all circuits to the relevant switches and device and earth them appropriately so that each device pretty well has its own circuit such as one has in a house. OK, so I use more cable than necessary, but it is cheap and using modern thinwall cable, the loom is a mighty fraction of the size of the original. I have rewired my +2 incorporating a full EFI controller using thinwall and with the wires wrapped neatly away, one would be hard pushed to see the looms.

Sure it would be different if I were wiring up a run of several thousand cars and had to return a profit, and then yes, I would be jumping connections all over the place to save a few bucks on each car.

As for horns, outside of trucks, emergergency and specialist high end cars that used air horns, the standard Britsh car did not have a relay for the horn (what is the cost of a relay then? A shilling maybe. BMC had to make a million minis. Forget the relay and save £50k...) - 12V was fed to the horn/s on a purple wire, returned to the horn button that was earthed to the steering column when pushed. They were not fused as many a Mini owner will testufy when they removed their steering wheel for the then go fast badge of a wooden Mota Lita wheel when they let the centre wire fall into the steering column that resulted in horns blaring and panic (hands up how many were caught out with this... :D )
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PostPost by: HCA » Sun Feb 28, 2021 10:56 am

Bushwacker wrote:As Monty Python would say: "And now for something completely different".

Here is a different style of diagram which some may find easier to look at and think through. Not concerned about where items are located in the car, just how one thing connects to another.

Have a look at this and let me know what you think of this.

Thanks,
Eric

Lotus Elan wiring diagram pictoral style_022621.pdf


That is pretty good Eric. I confess to not following the earlier part of your post as conventional diagrams bore me no end, but as Billwill notes, one just needs to see where it all goes without having to trace a run all around a page. But you have gone a long way to obviate the nonsense.

I urge you to spend some more time and maybe change some of the wire colours to conform more with the convention of the day - but I appreciate that the convention did not mean much to Lotus...

I second the suggestion that you need to incorporate the switch and relay inner circuits to cater for those not using or cannot use the original switches. Another point [I am surprised most diagrams do not show] is the cable size on each circuit that is handy for someone replacing a length or even making up a new loom.
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