The Wiring Harness in my engine compartment is in need of replacement. Everything is working but it is in horrible condition. Are there any companies that make replacement harnesses that members here can recommend? I've contacted British Wiring but have not searched for any other manufacturers.

Any suggestions or experience in replacing the engine bay harness which I believe is the main harness?

 

I have used autosparks in the UK, and it was a very well made harness. All colours, ends, and even style of wire (cloth covered vs PVC) was correct. I believe that there is just one main harness, I don't think there is just an engine bay harness, but I could be wrong.

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

 

There is only one main harness which also incorporates the engine harness. Don't let yourself be fooled.
Replacing this harness is a major undertaking. I have been there and done that on friend's cars.
Unless you have experience in electrical systems, I would advise you to not to do it.
In my case I have a background with a 5-year apprenticeship as a radio/radar technician and hold a current licenced aircraft engineers' licence in electrical and instrument systems.
Even then I have to be very careful as these early electrical systems are not easy to work on.
If everything is working and you want to clean up the wiring I suggest cutting back into the loom and splicing new wires into the connections etc. Old car looms are a source of colour coded wires
If the loom covering is poor then it can be removed, and the loom recovered with black adhesive tape. Not concourse but practical.

 

I replaced every harness in my car including sub harnesses. It's no joke. All correct in black with blue fleck. Listen to Bill ~ as he says there is no engine compartment harness. A friend took the cheap route knowing his harnesses were in a poor state and lost his newly restored Mk2 to a car fire as a result and he had not insured it yet. It was not the fabric harnesses that failed but rather the PVC insulated harness parts that were cracking up in SA's harsh sun & engine compartment heat.

 

There is a specific black tape designed for this purpose rather than using the black plastic electrical adhesive tape readerly available. The electric tape tends to come loose after time and the adhesive glue becomes sticky and horrible.
This is Tesa tape which is a cloth fabric tape designed for wrapping and insulating electrical wiring. Used by Jaguar restorers.
https://www.ebay.co.uk/itm/252275241...Bk9SR96KqMSmYQ

 

I think it's your choice here. Maybe
And my feeling is that this company takes wiring harnesses from some manufacturer in the United States.
I just didn't search (because I'm inside the EU) from which one.

https://www.limora.com/en/jaguar/jag.../wiring-looms/

 

As Jagboi points out above. Almost all suppliers including Barratts, Limora, David Manners, Martin Robey, Norman Motors, Moss etc. are supplied by Autosparks today.

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

 

They supply almost everybody & their product is excellent & authentic right down to opaque Lucar covers on spades. If link won't open paste into your browser. It opens fine for me.

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

 

Hi and thanks for the responses. I have done some repairs to the harness using Tesa cloth tape mentioned above. The harness is compromised in its entirety after exiting the bulkhead. In fact that exit point is is one of the points of my main concern. The rubber grommet is missing and a previous repair to prevent more chaffing was to stuff a rag underneath the harness. There is no slack at that point and too many exposed wires to make a repair logical. There are a few previous repairs that were poorly done and having used the wrong gauge wire and colors. I have restored several cars before including replacing wiring harnesses so I'm not afraid of the job as much as I am of this loom causing a fire.

My plan is to remove the engine and gearbox in order to fix all the leaks - there are many. While it is empty I want to repaint the engine bay so removing the harness is a good idea, correct? It would also help in replacing the missing grommet on the right side of the compartment and the aged and hardened one on the left side.

 

I would strongly advise replacing the main harness. You are heading for trouble the way things are. You may get away with leaving some of the sub harnesses if they are still OK after careful inspection.

You also live in a sunny part of the world! People in cold countries don't suffer what we do. Their concern is usually rust.

 

Agreed Glyn! The old harness is not worth saving. Once I have the time, I will start the engine removal and document the whole repair and hopefully post it here. I'm sure it will lead to more repairs or restoration, e.g., refinish the Dash!

 

Which gets me onto another point.

Warning ~ Fuse values


Also remember that Lucas fuse values of 35 & 50 amp etc are old British 1 second blow standard.

Fuses you buy today unless you order specially are American Carry Current rating.

In modern fuse values you should select a fuse of approx half the value of the Lucas rating shown in Jaguar Manuals.

e.g. Lucas Horn fuse = 50 Amps. In modern US rated glass fuses you should fit 25 to 30 amp.

Failure to do this could cause a fire in our car's wiring in case of a short.

 

The horn circuit was one of my first repairs! Someone ran new wires form the relay to the horns. A really botched job by the way. I rewired and also found the 50 amp fuse was blown. Replaced it with one of the original spares in the fuse box. No problem with the horns now.

 

Interesting that you are aware of rewiring a harness to previous cars but are you aware that the wiring harness for the Jaguar goes through the sill. Not an easy job to replace as you are having to thread the harness through a small hole in the sill in the front foot well then you have to pull it through and out of the sill just behind the rear door. At the same time half way along the sill at the B pillar there are wires that go up the B pillar to the door light switches and the internal lights. Not an easy job unless you are replacing the sills and then you have to be careful of burning the loom when you weld the sills in place. Even harder with an S type that has a third center membrane sill with holes in which the wiring loom loops through. I think Glyn has some photos of the loom running through a Jaguar sill.
Just saying.

 

Pulling the main harnesses is no fun & we did not have the old harness to aid this. My car was stripped of all harnesses prior to media blasting. We used an electricians conduit wire puller. My sills were rust free. Boroscope examined via the plug in the rear wheel arch. This car has harness temporarily held in place by Zip Ties. This is member Orlando's car under build. The S Type has a 3 piece sill unlike the Mk2 to stiffen the car. Much of the harness is behind the Dash. The earlier cars are somewhat different to the S Type.

 

Hmmm. I'm going off what the manual describes and the different sites selling the harnesses. Manual says there a four harnesses. The Forward, Panel and two Body harnesses. The main is the one I need to replace and according to the manual it is separate from the body harnesses that run down the sills. I'm assuming the Forward is the Main and they have a junction with the body harnesses behind the sills

 

I wish things were as simple as that Drawing looks. I don't have decent pics behind the dash. It's just the sheer volume of wiring.

 

We refurbished all the gauges. Process in my thread.

 

Good. If you had put in a 50 AMP US carry current fuse your wiring would fizzle with a short. I don't think people realise how high 50 amps US rating is.

 

This is what the wiring behind the dash looks like when the dash is stripped out on an S type. Good luck.