Lotus Elan

S1/S2 wiring loom

PostPost by: paddy » Fri Mar 06, 2009 12:03 am

After failing an MOT today with a sudden failure in the wiring loom (still to be traced, but somewhere in the morass of wires behind the dash) I've pretty much decided to replace the loom. This isn't the first time something like this has happened (eg indicators suddenly dying) and it's only a matter of time before it lets me down in a really inconvenient or dangerous way. Almost every connection and every soldered bullet seems fragile - either coming off the end of the wire or slipping out of the connectors.

I also have lots and lots of wires that seem to go nowhere - many obviously the result of something having been fitted and then removed again, but many looking like totally original wiring - just not connected to anything. I'm not at all convinced the loom I have is original, which makes me feel a lot less guilty about replacing it.

Now, SJ Sportscars list a loom for S1-S3 - but the wiring diagrams in the manual seem to suggest that the S3 loom has quite a bit more in it than the S1/S2 (eg courtesy lights, windows and some other things). Does anyone know if a S1/S2 loom is produced by anyone? Are they really that different? (Although the wiring diagrams look totally different, the S3 one mainly looks more complex because all of the earth wiring is shown explicitly and the layout more accurately reflects the actual layout in the car.)

Whatever loom I source, there's also a bit of additional wiring needed for things that have been added (eg alternator, electric fuel pump, fan, headlamp solenoid) so I'll want to be able to add those things just as if they had been an integral part of the loom, or I'll end up with a brand new loom and still have lots of odd and stray wires around. If the loom is fully taped up like the originals are, that'll be a real pain. Does anyone have any suggestions? I'm tempted to start from scratch and do it myself but I know that will take a lot longer and I'd rather be driving the car than rewiring it.

All insights welcomed.

Paddy
1963 Elan S1
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PostPost by: stugilmour » Fri Mar 06, 2009 1:26 am

I went with a Premier Lucas Uni-Loom supplied by Spyder for my Plus 2. You can google and you will find some comments on this forum and others. Some like it, some do not. It is quite a distance from stock Lotus, but generally follows the same configuration, colours, etc. Generally the wire colours honor the Lucas colours I found on the 'net. Uses modern wire and connectors, which again some like and some do not.

Note the one I got (not sure of the particular model number, but Spyder would be able to advise) a is sort of universal fit affair with the correct British wire colors, and judging by the number of included grounds is meant for a fibreglass car. Finding it relatively easy to modify as required as the front and rear looms are within rubber tubes rather than taped. Has ended up being changed quite a bit, but appreciated having a starting point. Probably as much work as just making one up, but I suppose it depends on preference and comfort with the mysteries of auto wiring. The runs in the dash area are just secured with twist ties, so very easy to move wires about one by one. Comes with plastic ties to bind it together when ready to install.

Some of the items I have been modifying/adding include:
[list=]Flasher circuit is set up for one flasher relay rather than two, so finding that part a bit of a puzzle.
Adding some relays to allow the hazard switch to work correctly with the stock switches rather than with a more complicated modern switch.
Adding relays for common functions such as heater, cooling fan, headlamps, window lifts, etc.
Additional fuses.
Additional courtesy light wire required.
Beefing up the wire size on several circuits.
Has front, dash, and rear ground wire runs, which I will connect to the bobbins.
Needed to add ground wires to several things
Just preparing to locate the new fuse and relay boxes. Putting them into the back of the glove box as recommended by Spyder. [/list]

One thing for sure is to invest in very good crimping tools before you do the job.

HTH
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PostPost by: Greg Foster » Fri Mar 06, 2009 2:20 am

Paddy,
HTH is right invest in a good crimping tool, especially if you use the bullet connectors . Also I coated all of my connections with copper anti seize. In the US I orderd a wiring harness from "British Wiring" www.britishwiring.com/ and was very pleased, they had Bullets and sleeves,various wiring connectors, wire, harness tape, crimp tool, etc.etc. I decided to go with the standard wiring in my late Series 3 elan(SS with rocker switches)....trying to keep it as original as possible. The main wiring harness is the same as the S1 harness with an add on loom for electric windows. The original harness had been wrapped over again with wires for brake fail switch, flasher warning , electric washer pump....I think that's it. I did the same but I also ran an extra ground system from the battery to make sure of no problems. For future connections I ran a new heavy wire with an inline fuse from the battery to under the dash, in case of radio, jacuzzi hot tub, aluminum smelter etc.. and have my fuel pum connected to this for now. Everything looks correct under the hood now. One thing I noticed is there must be a neater way to run the wiring to all of the dashboard controls. I just left it as I found it. Good luck!

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PostPost by: RotoFlexible » Fri Mar 06, 2009 2:25 pm

Paddy,
I did a modified version of "from scratch" during a recent extensive overhaul. I had the front loom completely out of the car, unwrapped, and staked out on a long board, with all the breakouts marked. I rebuilt it in place (rather than creating an entirely new loom) by replacing the wires that needed replacing. That included all wires that penetrated the firewall and many of the underdash wires. I also incorporated modifications for items such as the alternator, electric headlight lifts, new fuse and relay panel tucked under the dash, pre-engaged starter etc. I did a lot of planning ahead of time, created a spreadsheet recording all the old and new wires, etc. (This helped when I placed the order for the new wires.) It was a big job but one benefit is that I now know exactly where everything goes and can trouble-shoot more easily - although so far there has been no trouble!
I replaced a lot of bullet connectors (the appropriate crimping tool is absolutely essential, and use the correct bullet for the wire gauge) but many under the dash were OK.
If you are looking to pass your MOT and get back on the road quickly, this is not the way to go - it is a good winter project but not something you can do in a hurry. As always, when troubleshooting, suspect the earths - also, the overloaded and by-now grungy fuse box is a good place to look for problems. Good hunting!
Andrew Bodge
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PostPost by: twincamman » Fri Mar 06, 2009 3:01 pm

Paddy --I bought as many rolls of different colored wire as I could find and soldiered ever connection and used a modern fuse box . This his took 2 weeks and when I to do it again I would use a painless wire harness . soldiering the connections improves the reliability immensely but its a large undertaking ---ALSO ---install a master off switch close to a convenient location to save the car when the inevitable short circuit gets wired in ----in fact I have one wired into each lotus I own along with a a fire bottle ---=-ed
Last edited by twincamman on Fri Mar 06, 2009 6:47 pm, edited 1 time in total.
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PostPost by: twincamman » Fri Mar 06, 2009 3:03 pm

Paddy --I bought as many rolls of different colored wire as I could find and soldiered ever connection and used a modern fuse box . This his took 2 weeks and when I to do it again I would use a painless wire harness . soldiering the connections improves the reliability immensely but its a large undertaking ---ALSO ---install a master off switch close to a convenient location to save the car when the inevitable short circuit gets wired in ----in fact I have one wired into each lotus I own along with a a fire bottle ---=-ed
dont close your eyes --you will miss the crash
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PostPost by: Emma-Knight » Fri Mar 06, 2009 3:55 pm

I had the same problems with my S2 loom... :roll: - but - I fixed it... :D
The loom is quite simple, it just suffers from owner mods and bypasses and a general design error with those bullet sleeves. The Bullets, no matter what style, are mostly fine. The original soldered ones can be soldered off and refitted to the refreshed end of the old - or a new wire. The original bullet sleeves had too strong fixing dents, which even with oil or copperslip, made undoing almost impossible. If you take those new sleeves with tiny fixing dents (these can be fitted to original rubber sleeves for the original looks) it will come together easier and will be undoable without damage.
The black wrapping tape is a non adhesive stretch fixing type. You can put it back (or buy new one) and just glue the end slope to prevent undoing.
It would require step by step checking. When undoing the wrap, you can build your own alternater set up - even with correctly coded wires...

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PostPost by: paddy » Sat Mar 07, 2009 6:43 pm

Thanks folks for all the advice. It sounds like the general preference is to restore than completely replace.

The immediate problem is found and fixed. I'm still not sure whether or not what I have is original but I'm going to stick with it for now, remove all of the extraneous wiring and assess the condition of what I'm left with. I've checked and taped up as many of the loose ends as I can without removing the dash so I'm not as paranoid as I was before :) A 6-way spade-type fuse box had already been fitted by a PO so at least individual problems are less likely to take everything else out.

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PostPost by: twincamman » Sat Mar 07, 2009 7:16 pm

Paddy I would suggest shrink tube instead of black tape ---ed
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PostPost by: Elanintheforest » Sun Mar 08, 2009 8:30 am

I've used thes guys for several different cars:
http://www.autosparks.co.uk/
Their product has always been spot on, with the cables just a tad longer, which helps. they will also wrap the loom to original spec or a later spec if you wish, and will built you a custom loom with mods that you specify.

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