Wiring Harness

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ALF
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Wiring Harness

Post by ALF » Wed Oct 22, 2014 6:55 am

Has anyone experience with the wiring harness autosparks.co.uk is selling?

Based on the information on the shop they don’t provide wiring diagrams or any other kind of information. After contacting them and asking for pictures they told me that every harness is customized and therefore no reference…. :|

Would appreciate some more inside information and details as I’m looking for a harness with braided cables and the correct look.
Thanks

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Roger King
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Re: Wiring Harness

Post by Roger King » Wed Oct 22, 2014 9:51 am

I've used the Autosparks harness in three cars, the MkII twice and a modified MkIII once. As they have said, their harnesses are made from pattern originals and as we all know, no two Cobras are the same and very few left the factory the same. The harnesses are certainly pretty good and use (mostly) the right materials and, of course, colours, as these were universal for any Lucas products. Some things you may like to consider:

1) SVA/IVA - the Lucas harness is laid out exactly (within reason) as original. There is therefore no provision for side repeaters, alarms, immobilisers, extra relays, brake fluid level warnings etc. From experience, the easiest way to get a car through SVA is to build it using Gerry's harness, pass the test, then take it all out and start again with the Lucas harness.

2) With the Lucas harness, you will only have a max of 4 fused circuits as this uses the original black bakelite Lucas fusebox. No components have relays, but I added a pair of 6RAs for the horns and the cooling fan.

3) You will need a lot of time, patience and extra materials to make it fit, together with a basic undestanding of sixties car electrical systems. It is not a simple 'fit and forget' option, as there are slight variations in production and it will probably not be a complete harness depending on what you are trying to fit to your car.

4) Diagrams! Well... there is a wiring diagram for the MkII in the AC Drivers' Handbook published by the ACOC as a reproduction. This is rudimentary at best, with several circuits missing, and assumes the car to have the correct voltage regulator and dynamo. It's a bugger to read, but does help. There is a better diagram available for both the MkIII 289 and 427, which according to AC have the same harness, printed by the factory but apparently for the US market, so this has a Ford alternator with an Autolite external regulator. This is a much better and more complete diagram which is extremely useful. Also of great use is to get your hands on a diagram for a sports car of similar period - Healey, Triumph etc. and just see how they did things. I'd also recommend Rick Astley's Classic British Car Electrical Systems, a very helpful book on car electrics all round.

5) Wipers. All Cobras used the DR3 six-wire (not the similar five-wire) square cased wiper motor, with reverse park down on to the front scuttle. No Cobra, ever, had the round case W-style wiper motor. The Autosparks (Lucas) harness is wired for the correct motor, so there is a great bundle of wires for the wiper motor, and the other end for the switch. This type of motor will only work with the correct PRS7 Lucas switch - motor and switch were used on XK Jags also but are not cheap.

6) DB10. Every Autosparks harness I have seen is designed around the Lucas DB10 flasher/brake light relay, so would not work with separate amber indicators - or would need so much butchery as to make it a rather pointless exercise. This may not apply to the one they list as for the 427, with PVC taping - you'd need to ask if this is what you want.

I'm sure there are other things I've not mentioned, but this is enough to be going on with - good luck! How badly do you want to do it? If you're handy with a soldering iron and have plenty of time it's perfectly do-able.

Roger

With regard to their harness being 'customized', they seem to know their Cobras as they will ask where you want the DB10 relay positioned (most UK cars had this mounted down by the front of the engine, whereas US cars had them on the bulkhead), and obviously if you want anything anywhere else they can do that too, usually leaving long loose leads for you to finish).

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Re: Wiring Harness

Post by ALF » Wed Oct 22, 2014 12:43 pm

Hi Roger

MANY THANKS for your interesting and helpful replay.

My intention was first do it by my own but as I would need to order the cable per meter it seemed to me an entire harness would be easier instead of gassing the length of >60 different cables and order them in advanced.

I’m quickly going to some of your points:
1) As I don’t have any side repeaters, alarms, immobilisers, brake fluid level warnings etc on my car and there is no SCA/IVA requirement the Lucas harness would be fine.

2) In the past I made some enhancements on the current harness which I’d like to have incorporated on the lucas harness.
- separation of the fans. Puller fan via thermostat or dash switch and dual front fan only via dash switch. This switched via some relais to have the circuit between “switch and fan” separated and to activate it in case of need.
> It looks to me you made the same enhancements. :D
> How did you use the 4 fused circuits? Switching circuit, fan, light, starter, …

4) I used until now the diagram shown on the 289 manual page 52.

5) I’m currently restoring a DR3 wiper motor and was investigating for the PRS7 switch.
There I found some diagrams using a 2 circuit switch and a relais which could be an interesting option.

6) As no separate indicators are required the DB10 flasher/brake light setup is the way to go.

My fear was that e.g. the DB10 would be on the wrong place, but as you mentioned they’ll ask for placement details this should not be an issue.
Based on your information they would be a great source and are asking the right questions.
ALF

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Re: Wiring Harness

Post by Roger King » Wed Oct 22, 2014 1:20 pm

From what you say I don't think you'll have any big problems. I'm just completing my latest Cobra wiring now using one of these, but this is the one wired for Ford alternator so is proving a little... interesting.
Making up a loom yourself would be a very expensive way of doing it, I reckon. Also, you wouldn't be able to do the cotton braiding outer cover, you'd have to do it all in wrapped harness tape. Which is fine, but...
Yes, the alterations you suggest are pretty much what I have done. For fans etc. I make up a small ancillary harness to route alongside the main one. Beware of asking for extra wires in the main harness, as this makes it much stiffer and hard to work through gaps etc. (ooer missus). I asked for heavier main charging circuit cables to handle greater alternator output and it's proved a real pain, especially with things like ammeter connections.
It's worth telling Autosparks where you want the DB10, and also what alternator (dynamo, if you're mad) you will use etc. Give them as much info as you can, but be prepared to modify bits - the originals were so variable, they can't be expected to get it just as you want first time. It's not like my Cooper S, where the loom for that model just fits perfectly, down to mass production. I use Autosparks for all my harnesses if possible and have very few problems.
The PRS7 wiper switch is probably the hardest part to find, and I have yet to discover if converting to negative earth is going to affect this - hopefully not, as many XKs have been converted. Be aware there are a number of PRS7s, some are light switches and are different. The correct type has several screw connections on the base.
Fuses - I use the same basic setup as p.52, i.e. one for heavy current permanent lives (browns, etc.), one for switched ignition lives (whites and greens), one for lower current permanent lives (reds etc.) and I use the fourth for the mods, i.e. horn and fan relays.

Here's the MkIII diagram - much more use:

Image

Just noticed, this says 'negative earth' so wipers etc. should be OK. Wiring the wipers and switch is complex. If you search some of the XK Jag sites you should be able to find which goes to where on the switch. Also some 'interpretation' is needed of the colours.

I keep editing this and it's getting longer and longer, so that's it for now!

Roger

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Re: Wiring Harness

Post by ALF » Thu Nov 05, 2015 1:08 pm

Hi Roger

I was in contact with Autosparks the past days and they can not provide me the required loom (customized according the following details) :?

Image

Did you use the UK version (Voltage Regulator on left engine bay) or the US version (Voltage Regulator on Bulkhead)?

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Re: Wiring Harness

Post by Roger King » Thu Nov 05, 2015 1:13 pm

Hi Alf,

I used the Autosparks stock UK RHD version converted for alternator, external regulator. For the extra wires for the Autolite regulator I specified colours and length of wires. My regulator has ended up on the R side footbox (as ever, 'sides' are as viewed from sitting in the driver's seat), but would probably be better on the L side. My alternator uses original cast brackets to hang off the R side cylinder head.

Roger

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Re: Wiring Harness

Post by ALF » Thu Nov 05, 2015 1:30 pm

Hi Roger
Thanks for your fast replay!

I'll challenge them to provide me the details about the gap between the default and my wish.
Unfortunately (at least the person I'm in contact) has no idea about the way there LHD #933 harness gets built. :shock:

Could you please help me and thell me from your expiriance what would be not at the place I'm expecting it. This would be a great help for me to get a usefull feedback to understand if the default would work and what needs to be changed. :D

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Re: Wiring Harness

Post by Roger King » Thu Nov 05, 2015 2:19 pm

ALF wrote:Could you please help me and thell me from your expiriance what would be not at the place I'm expecting it.
Not sure I understand the question...

You might do better to use the stock RHD harness and modify it yourself. This is what I did with my first Hawk and whilst it's fiddly, it's pretty easy to do as long as you have worked out the wiring diagram. You can get wires in all the correct colours and PVC harness tape to wrap the modifications.

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Re: Wiring Harness

Post by ALF » Thu Nov 05, 2015 3:01 pm

Roger King wrote:You might do better to use the stock RHD harness and modify it yourself. This is what I did with my first Hawk and whilst it's fiddly, it's pretty easy to do as long as you have worked out the wiring diagram. You can get wires in all the correct colours and PVC harness tape to wrap the modifications.
I'll do so and hope the defult harness (incl. the Alternator Version) will be ~90% OK.

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Re: Wiring Harness

Post by Roger King » Thu Nov 05, 2015 3:18 pm

ALF wrote:
Roger King wrote:You might do better to use the stock RHD harness and modify it yourself. This is what I did with my first Hawk and whilst it's fiddly, it's pretty easy to do as long as you have worked out the wiring diagram. You can get wires in all the correct colours and PVC harness tape to wrap the modifications.
I'll do so and hope the defult harness (incl. the Alternator Version) will be ~90% OK.
I should mention that I've had 3 of these and they've all had subtle differences - there was no such thing as a 'production' harness for a Cobra 289, there were so many individual variations. My Mini was easy, everything simply in the right place and just connecting up required - but Cobras are different, not just in wiring. The only mods I personally had to make were to customize to my own car. Lighting, fusebox, other stuff in all the correct places.
You need to be sure that your car (Hawk or whatever) will have all the components in the correct position for an original car - Autosparks can't know what a Hawk requires, as their loom is for an AC. For example, you need to have the brake light switch on the rear chassis tube etc.

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