Thanks for the pic Rob and once all that is in a restricted space with the front of dash in place it becomes a nightmare.

One of the greatest difficulties we had other than that was T'ing in those cursed harnesses up the B pillar that you mention earlier for the interior lights & switches. There is so little access space to the sill harness. I took a drill to my LHS to increase it a bit. The air was blue with bad language.

 

Pulling the harness through the sills and door posts is not easy. The canonical method is to attach pull strings to ALL the old cable ends before pulling them out. Of course, once the old ones are out, you are committed to getting t!he new harness in. Another possible problem arises from whatever a previous restorer might have done, adding obstructive intermediate sills and reinforcements at the door post to sill joints, attaching the harness to prevent it moving around/keep it clear of welds - a lot of people think those cable ties are standard. If there are any doubts about the sills or if the door fit looks off (which usually means the bottom of the door posts need work), I'd be inclined to cut the outer part of sills off. It's then possible to do any necessary panel work and more easily replace the harness.

Of course, once you've got to the old harness, it may all be unnecessary as the part running through the sills is very well protected.

 

The Zip Tie was only invented in 1958 and Jaguar did not use them on our old cars. What they did use on some cars was stripping with multiple holes equidistant from one another & a pop stud that went through selected holes on both ends once suitably trimmed for length required.

On the OP's S Type I would replace the main behind dash to engine compartment harness at minimum. Then plug all the sub harnesses into it if considered in safe condition.

Generally monitored by which fuses blow regularly & why.

 

One of the signature limitations of the Mark 2 wiring is that there are only two fuses to protect the whole system. Not only is this a very poor protection scheme but it also makes trouble shooting very hard indeed,

I fitted a standard new wiring harness to my car and added a multiple fuse block. This is very easy since the power wires all converge at the original fuse holder and it is a simple matter to spread them out individually so that each one has its own fuse.

Attached is a copy of my supplemental manual that shows some of the details. Although I have done many other modifications to the wiring at least you can see the multiple fuse approach I took.

Also attached is the maker data sheet for the fuse holder.


Attached Files

 

There's a photo in Paul Skilleter's 'Jaguar Saloon Cars' (and I think some of the other books) of an S type 'rolling chassis.' It has no external panels and, in particular no outer sills. Since there's no outer sill to constrain the harness, Jaguar attached it to the intermediate sill (probably with their usual pop studs - it's hard to be absolutely sure from the picture). It could be as a consequence of seeing it, that a few people feel they should fasten the cable to something.

Paul wrote that the car was for a European coach builder - I wonder if it became either the Frua or Bertone S type?

I don't recall either fuse ever blowing in my Mk2. Though given their size (rated current, fast or slow blow) it's not surprising without a very serious short circuit.

 

Yes ~ the S Type (which we are discussing) is a little better protected with about 8 or 9 fuses dependent on the configuration ~ eg OD or heated rear screen etc. etc. They kept adding inline fuses as the car matured. I think the very early cars had 7. No S Type ever had an alternator as an example. One of the very early changes was a fuse on the OD in case the solenoid ever got stuck in the high draw mode.

 

I understand I'm up against a difficult job. It is not something I want to do but the current harness is in such a degraded state that even trying to repair it is futile because it will continue to deteriorate. I don't want wires shorting out leaving me stranded or worse causing a fire. Most of the cloth covered wires are loosing their covers while the PVC covered wires are hard and brittle.

 

When the PVC gets brittle & will crack the harness has had it. Leaching of plasticiser. We are talking old PVC technology of the time. Your new harness will not suffer this in your lifetime. Far greater plasticiser stability.

 

Now I understand what Felixbobcat is concerned about and I agree a new harness is definitely in order.
At this point may I suggest photo and photo and again photo every connection.
It is extremely important to photo the behind the dash switch panel connections on every switch.
In addition, try and remove the loom in one piece and label every connection even though it will be eventually discarded.


I have just gone through this process with a friends E type. and am prepared.
The bare body shell is in a rotisserie and I expect it could be 12 months at a minimum before the new loom will be fitted
Cheers

 

Labelled everything is a great help, also is having a wiring diagram in colour if you can find one. For the E Type, I got it printed poster sized and hung it next to the car, that was a great help.

 

Have this blown up & laminated. What I have on my garage wall. It is high resolution as you will see if you blow it up. Just download the pdf & blow up & you will see what I mean. And it's fully colour coded.

https://www.jaguarforums.com/forum/a...ram-hi-res.pdf


Example ~ S Type.

 

Wise advice Bill. Having done it, the number of sub harnesses on an S Type is huge. And Jag do so many loop backs. Like that bundle of double connectors ahead of the wiper motor.

A further example ~ and you can keep on blowing it up without it falling apart. It is proper hi res. See example above of cigar lighter

 

Felixbobcat
What sort of Jag do you own?
Ther are major electrical and wiring differences between MK1/Mk2 and S types.
The Mk1 and MK2 are relatively simple with only two fuses in the whole car in the engine bay
The S type is much more complex with a number of fuses incorporated in the instrument panel etc.
I am just trying to ensure you get the correct advice for your car.
Cheers

 

I’ve got a 1966 S Type

 

And the high res colour diagram I have provided is for the S Type. I took a look at your profile to see what car you had. Stick it in your signature as well then people can see easily as I have below.

 

Wrong thread ~ Sorry Felix.

 

Thanks Felix.
My "expertise?" does not run to S types which are fairly rare in Australia because the hot rodders got them for the rear ends when they were worth very little.
So, I will quietly withdraw from this post and let the S type gurus like Glyn and Jagboi give you advice.
Cheers

 

Happy New Year Everyone!

 

And the same to you & all!

 

Happy and healthy New Year!