Lotus Elan

Sprint Dash Harness to Main Harness Connections

PostPost by: pharriso » Mon Feb 24, 2014 7:56 pm

A number of companies sell replacement wiring harnesses for the elan, normally they are split into 3 sections, engine bay, cabin & trunk.

How do these harnesses connect together? Are the wires terminated in bullets & then single bullet connectors? Surely there would be a great number (20+) where the harness comes through the bulkhead... Anyone have a picture?

It looks like my harness was cut at the bulkhead behind the dash & rejoined using nasty blue crimp connectors... wondering what the best way would be to fix this?

TIA
Phil H
Last edited by pharriso on Fri Jan 11, 2019 11:07 pm, edited 2 times in total.
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PostPost by: Bill » Tue Feb 25, 2014 12:47 am

Phil

I am sure would like a recomendation for the best supplier, I have the coupe to do.

PS We have 12 inches of snow here in Sibell Bay, I had to bust out in the Tundra this morning.

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PostPost by: fatboyoz » Tue Feb 25, 2014 5:00 am

Phil,
The connections are via bullets and connectors. Some connectors are single, some are doubles with one in and two out (common source to power two items). You can also get multiple connectors with up to 5 individual channels (for want of a better word) that can reduce the number of single connectors. The wiring diagram shows which wires are single and which ones are bussed together.

My 3 new harnesses were obtained at Paul Matty in the U.K. and were nicely made.

The fix for a butchered harness could possibly be more difficult than fitting a new one. Repairing the original, insitu, is probably going to be a problem due to lack of room, and perhaps shortness of the wires.

I have included some photo's of my loom connections.

Cheers,
Colin.



pharriso wrote:A number of companies sell replacement wiring harnesses for the elan, normally they are split into 3 sections, engine bay, cabin & trunk.

How do these harnesses connect together? Are the wires terminated in bullets & then single bullet connectors? Surely there would be a great number (20+) where the harness comes through the bulkhead... Anyone have a picture?

It looks like my harness was cut at the harness & rejoined using nasty blue crimp connectors... wondering what the best way would be to fix this?

TIA
Phil H
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PostPost by: pharriso » Tue Feb 25, 2014 11:44 am

Thanks Colin, I would not describe my harness as butchered, just that I am particular & am returning everything to how it should be.

I'm replacing all red/blue modern splice connectors with the correct Lucas connectors & will replace those harness to harness connections with bullets & connectors.

Thanks for those pictures, didn't realize that isolated connectors like that existed. I have ordered 6 3way isolated connectors, certainly better than up to 18 individual isolated snp connectors.
Last edited by pharriso on Tue Feb 25, 2014 4:20 pm, edited 1 time in total.
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PostPost by: lotusfan » Tue Feb 25, 2014 2:13 pm

Phil

Just to add a little more information. When I dismantled my Sprint there was a large white plastic multi-way connector joining most of the dashboard loom to the engine bay loom. It's the white rectangular block to the right of this photo.

100_2415.JPG and
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PostPost by: pharriso » Tue Feb 25, 2014 2:22 pm

lotusfan wrote:Phil

Just to add a little more information. When I dismantled my Sprint there was a large white plastic multi-way connector joining most of the dashboard loom to the engine bay loom. It's the white rectangular block to the right of this photo.


Interesting, do you have a larger (than about 1") hole through your bulkhead for one half of that connector to pass through?
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PostPost by: lotusfan » Tue Feb 25, 2014 3:16 pm

Phil

The connector would not quite fit through the wiring loom hole in the bulkhead. To strip the loom out I had to cut the connector off. My new looms came with pins and sockets for the connector body so you feed the engine bay wires through the bulkhead and then fit the connector half. The pins and sockets were different from the usual bullet connectors,
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PostPost by: gjz30075 » Tue Feb 25, 2014 5:19 pm

No need to cut the wires. The wires are held in with a tang, of sorts. This tool is made to slip over the tang to lower it, to allow the wire to be pulled out of the plastic plug.
http://www.amazon.com/Lisle-57750-Wire- ... B007WQQHA2

That said, I'm assuming :-( that the Lotus plug is universal and the wires are held in this way. I can't imagine any other way, but, then again, this is Lucas.

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PostPost by: pharriso » Wed Feb 26, 2014 3:23 pm

Just received what I would consider an authoritative response from Josh at British Wiring (http://www.britishwiring.com):

"The Main and Dash harnesses for the Lotus Sprints connect together using the 2mm pins/sockets. We are unable to source the original plugs for these, so you would need to re-use your original housings with the new pins.

The Series 4 Elan's used standard bullets to connect the main and dash harness.

All other series Elan's are a single harness for the main engine bay and dash area."

Unfortunately the original Sprint 12 way wiring connectors appear to be no longer available; However Tyco make a 12 way Mate-N-Lok connector similar to the original that is widely available.
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PostPost by: lotusfan » Wed Feb 26, 2014 5:48 pm

Very interesting reading Phil. My original housing was damaged as a pin had melted and I too used a Tyco Mate-N-Lok connector in it's place, the pins were a bit loose but it seems to be OK.
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PostPost by: pharriso » Fri Jan 11, 2019 11:07 pm

Thanks to Mike (LotusFan) I have reverse engineered the Sprint Main Harness to Dashboard harness connector & Connections.

The original connector was a 12 pin connector (4x3) with the male connector on the dash side housing female socket terminals. Amp/TE/Tyco Mate-N-Lok 12 pin connectors are a very close match and are relatively inexpensive; relevant part numbers are:

1-480708-0 1 x Male/Plug Housing
1-480709-0 1 x Female/Cap Housing
926893-1 12 x Female/Socket Terminals
926894-1 12 x Male/Pin Terminals

These are available as sets for less than $10 from vendors such as 3waycomp on eBay.

Both the Female & Male housings come with added mounting tabs for mounting on PCBs etc; these can be trimmed off to make the housings smaller.
matenlok_assupplied_trimmed_sm.jpg and
Connectors before & After Trimming

The male housing is smaller & after will fit through the loom hole in the bulkhead. Now is a good time to replace that ratty looking harness bulkhead grommet.

If you look carefully at the wire side of the Mate-N-Lok connectors each position is numbered:
img_9815.jpg and
Terminal pin numbering


Wires go into each of the cavities per the following sequence:

Pin # Wire Colour(s) Wire Function
1 RB Low Brake Fluid (Sovy)
2 WR Ign, Switch to starter Solenoid
3 WP Power to Ignition switch
4 PB Horn
5 LtGB Screen Washer fluid pump
6 UY Headlamp Flasher Relay
7 UB High Beam
8 NY Ignition light
9 W Ignition Feed (Hot Ign on)
10 UN Low Beam
11 P Cigar lighter (Hot all times)
12 W Ignition Feed (Hot Ign on)

You may be wondering why I am going to this trouble; this is what I found under my dash:
img_9823.jpg and

There is no way my OCD will let me live with this....
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PostPost by: gjz30075 » Sat Jan 12, 2019 12:35 am

Phil, please post pics of the finished product.
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PostPost by: lotusfan » Sat Jan 12, 2019 3:39 pm

Hi Phil

Many thanks for the name check - fame at last!!! Pleased to have been able to help.

You give the part numbers of the housings and pins, don't you need a dedicated crimp tool also for the pins?

Your OCD is maybe a bit OTT, those blue crimps look quite tidy, the DPO could have used chocolate block (terminal blocks) instead which would have offended.

Maybe you can be forgiven though, given that your Sprint is LHD there must be a multitude of wiring joints in that area what with the engine bay, dashboard and rear looms as well as lighting and indicator and starter wiring.

Were these multiway connectors Lotus moving into eaasier wiring? Are there similar connectors in the later Elan +2 wiring looms?
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PostPost by: pharriso » Mon Jan 14, 2019 8:14 pm

lotusfan wrote:You give the part numbers of the housings and pins, don't you need a dedicated crimp tool also for the pins?


Not specific to those terminals, any good crimper that does the wire crimp at the same time as the insulation crimp should be good enough. AutoSparks sell this one - https://www.autosparks.co.uk/electrical-components/wiring-tools/heavy-duty-rachet-action-crimp-tool-for-use-with-a-large-range-of-terminals.html

lotusfan wrote:Your OCD is maybe a bit OTT, those blue crimps look quite tidy, the DPO could have used chocolate block (terminal blocks) instead which would have offended.


I absolutely loath thos generic red/blue/yellow generic connectors... have rid my elan of them all. My main issue is that they generally clamp only on the wire insulation & seem to pull off quite easily. That & they look ugly...

lotusfan wrote:Maybe you can be forgiven though, given that your Sprint is LHD there must be a multitude of wiring joints in that area what with the engine bay, dashboard and rear looms as well as lighting and indicator and starter wiring.

On Federal cars we also have the dreaded DB10 relay box which takes the standard flasher, hazard & brake light inputs & converts them for the single bulb indicator/Brake rear lights.

lotusfan wrote:Were these multiway connectors Lotus moving into eaasier wiring? Are there similar connectors in the later Elan +2 wiring looms?


In a word Yes. Assembly line Speed / cost is all about Takt time & is limited by the slowest operation. Stuffing the loom must have been a slow operation at Lotus given the number & style of connectors.
S1-S3s had a single engine bay / Dash harness which meant the engine bay harness would need to be threaded through the Bulkhead loom hole. S4s had separate Dash & Engine bay harnesses, but the 2 were joined by 18 separate bullet connectors. Sprints have 1 12 way connector & 6 separate bullet connectors.

Yes I believe later Elan Plus 2s had 1 or more multi pin connectors.
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PostPost by: Bud English » Mon Jan 14, 2019 8:35 pm

If you stick with the aircraft grade or Mil Spec Thomas & Betts, AMP or Molex crimp connectors you can't go wrong. They all have a second lighter metal sleeve that crimps to the insulation in addition to the plated copper lug that crimps to the conductor. In a pull test the wire away from the crimp will break before the conductor pulls out.

That said, you can't beat the multi pin connectors, where you have room. You just have to ensure that they are rated for the correct current/wire size like you've done.
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