Has anybody ever overhauled the complete wiring harness on a
77 XJS v12 2 coupe with new wires, connectors, etc?

 

It's common to methodically (and eventually) remove/inspect/clean/tighten all connectors... and replace/repair them on an as-needed basis.

It's virtually a pre-requisite on these old Jags.

Is that what you mean by "overhaul"?

I'm not aware of anyone summarily replacing *every* connector

Cheers
DD

 

Im referring to replacing all the wires, connectors, etc. If cant find connectors then cut n solder new wires with old connectors, etc.

 

I've done the fuel injector harness and all other wires that ever ran in the "V" or anywhere over the engine. I'd suggest cross-linked polyethylene (Del City has it) as it will withstand much more heat than traditional wire.

I soldered virtually all connections and then used shrink wrap over the solder joints. In some places I used clear shrink wrap so I can inspect the connections.

Wires that ran only along the walls of the engine compartment I left alone as they still seem to be in ok shape.

Cheers,

John
1987 XJ-S V12
63,000 miles

 

I'm far from an expert on this, but I have looked into doing what you're describing. There are people that build replacement engine harnesses, sometimes with connectors, but they're pretty expensive. I don't believe (could be wrong, just hadn't seen one) that any of them use the exact stock connectors so they aren't quite "plug and play".

It is my understanding that when replacing sections of harness that one must either re-use the old connectors or fabricate some sort of replacement. IMHO each method has its ups and downs and what I've done so far is to re-use the old connectors.

I have done full scale wire harness replacements on a couple of vehicles and based on what I know it would be extremely difficult to do on the XJS unless you were doing a full tear down. You'd have to at least pull much of the interior out, probably the most difficult part being the dash. (If you ever want to try something like this, an old '60s era Chevy truck is relatively easy... an older Porsche 928 not so much.)

I did the injection harness but left the wires a bit long so I can replace the connectors. I think I'm going to cut the wiring harnesses that come into the engine compartment at some point and rebuild them. The big problem when doing that is you lose the ability to track wires by color - it's virtually impossible for a home builder to get the many different color combos used by the factory - but at least you get new wires that are properly rated for the temps found under the hood.

It would be really nice to be able to get stock connectors... I think my wires are OK up to those points. If anyone has a source... would love to hear about it.

Not sure if this helps answer your question or if it just says, "me, too".

 

My Jaguar XJS is a frame up restoration unless I find another car and use this one for parts.

 

Guess I wasn't much help, then, but now is certainly the time...

I have a really nice, full harness for my Porsche that I got off a donor car that was in fabulous condition - except for the body, since the car had been rolled. To get it out I literally cut the car apart. Even with the dash and interior gone there were sections that the connectors wouldn't fit through. I have no idea how I will install it in my "surviving" car but will try when the engine and interior are out. :-P

Other than that, I guess you will want to order as many different colors of wire as you can find / afford and try to get them as close as you can to stock. Make yourself some kind of "translation" so you can match the replacement colors to stock, or take a wiring diagram and change the colors on it to match your replacement.

Pull the current wiring out, keeping the harnesses together and intact wherever possible. One of the big tricks will be connectors. GM weatherpacks may be good candidates.

I'd be really surprised if anyone builds and sells most of the harnesses. If they did I would expect the cost would be astronomical. I'll be curious to see what you do so I hope you'll be willing to keep the thread updated.

 

*All* the wires and connectors?


As you wish . It's entirely doable. Buys tons of wire and a few dozen various connectors...lots of modern choices out there


But....unless the car has been in a fire or a flood you'll probably be making LOTS of extra work for yourself and spending LOTS of money you don't need to spend.


For example, a few years ago I bought an *entire* wiring harness from an early 80s XJ6 (only $75....best bargain I ever got!). About 95% of the wiring was absolutley pristine and maybe 8 or 10 connectors needed replacing. The problem areas were (no surprise) engine bay wiring (easy to make new) and connectors/lamps sockets that were exposed to weather.

(I'm still picking away at that harness when I need to wiring repairs on other Jags or even if I just need some good wire for a different project


Cheers
DD

 

Get yourself a Del City catalog, they have lots of connectors and such.

From glancing in their catalog it looks like you would be limited to only seven colors, at lest if you go with cross linked wire. Not sure how many color combinations there are in the car. When I redid mine (again, didn't do the entire car, just stuff that was over the engine) I used only two colors.

I wonder what the total length of wire in the entire car is?

Have fun with it....

John
1987 XJ-S V12
63,000 miles

 

What website for this del city catalog?

 

Car has no windows except for passenger side since 2005 and has been sitting outside.

 

Ugh!


Yeah, you've got a big job ahead of you.

Cheers
DD

 

Body is not too hateful. Floorboards are rotted 2 years ago. Its the car in my avatar.

 

This outfit has a bit of everything from the usual junky stuff to modern sealed connectors

Automotive Electrical Connector Pigtails, Terminals, Tools and More


Of course there are dozens of other good suppliers for automotive electrical supplies

Cheers
DD

 

There might be a few instances where an upgrade to something modern isn't practical. If so, this outfit has some of the 50s-60s-70s type stuff

Welcome to British Wiring - classic British car wiring harnesses and components

Cheers
DD

 

Dave

I own a 75 Jaguar XJ12C which was converted to propane and was missing a wiring harness. I bought two parts cars in order to convert it back to propane and I buddy of mine and I are currently working on converting it back together. As the wiring harness on both cars is cooked, he's planning to rebuild the wiring harness for the fuel injection.

We're able to get all the parts except for the big plug that goes to the main harness which will need to be salvaged from the old harness. If we can make it work, then our plan is to sell them so please keep my contact info handy.

Thanks

 

the big plug can be replaced with several other kinds if connectors, I did mine with a weatherpack connector.

 

Whats the website for the weatherpack connectors?

 

As provided earlier.....

Automotive Electrical Connector Pigtails, Terminals, Tools and More


Type "Weatherpack" into the serach box on the home page.

Or just Google "Weatherpack connectors". They're not hard to find.

Pico Wiring Accessories is one popular provider. Or Del City.

Cheers
DD