Where can I get a set of drawings that show the wiring harness numbers, routing, where the cables start and end and what systems the harness are feeding with the number and colors of the wires included in the haneses? For my 1989 Jaguar XJS v12 convertible automatic transmission, LHD Vin #157055

 

Here's a link. Diagrams at the top of the page.
JagRepair.com - Jaguar Repair Information Resource

 

That is very helpful, but those are more wiring schematics vs a wiring diagram.

Admittedly there are lots of wires on these car, and several wiring diagrams would be needed. Flipping back and forth to try and figure out what component is located where on one page, and then mate it to a schematic, can be frustrating and confusing.

Wiring diagrams show where in the car the wires are physically routed and to what components in their real close location approximation.

Thats one complaint I always had about these cars since my first, 1976 XJS.

This is closer to a wiring diagram:

http://www.ferrari308gtbi.com/img/e3082Va.jpg

Doug

 

Doug is correct. The wiring harness have numbers on them like 30, 34, Etc. What I need to know is what wire is in each harness and where it goes. I am trying to track down the brown/black wire from the alternator monitoring terminal D+ to the 100 ohm resistor next to the instrument panel indicating warning lights from the alternator (fig 10.1). I have located both ends of the wire and CF1 but there is no continuity. There must be a break in the wire somewhere. It would be helpful if there were drawings showing which harness the brown/black wire jumps in and out of to locate the fault or I will have to run a new wire between the alternator and the instrument panel.

 

Something like this?



I've not seen any such illustration in Jaguar literature; I wouldn't waste too much time looking

Anyhow, a poor connection at CF1 itself is common. Corrosion, dirt, etc.

You could disconnect the CF1 connector and test the exciter wire upstream of CF1 and then downstream of CF1. This would at least tell you which side of the firewall your break is.

Faults are more likely in the engine bay due to the heat roasting the wires. And, in my experience are most common near the termination points. So I'd first look near the cluster, near CF1, and near the alternator itself. Wire breaks in the miles of wrapped loom between these points would be less likely, IMO

It might be difficult or near impossible to locate the cabin side of CF1. I think it's buried behind some HVAC stuff....but my memory is foggy on that

Cheers
DD

 

If you look on the diagrams I provided a link to, the connections are shown with a code such as CF1 on figure 2.2 of the '89 diagrams. The key to the codes and connector locations are shown on figure 1.1 of the 1989 electrical diagrams. For example, CF1 is the right bulkhead connector. All of the wire colors are on the diagrams. Just take a few minutes with the diagrams, and it will become clearer. Just be sure to use the correct diagrams for your VIN, as there was a mid-year change.

 

All that info is in the guides available on Gus's site.
the individual diagrams identify the wire along with pin number of relevant plug/socket and the harness layout / connector location page gives you the location.
Some of the earlier years are a bit more problematic but '89 has all that data available.

 

Where is Gus's site?

 

The one I directed you to in post #2 above.

Jon

 

And we circle back around to post #3.

Doug

 

In the time spent hashing out the semantics of Wiring Schematic versus Wiring Diagram the open circuit could have been repaired

Cheers
DD

 

Thank you for the links to the drawings. I already have all of the electrical drawings in the links. I am a Master Electrician and worked in the electrical industry for over 46 years worked with 100,000 volt systems on down to milliamp controls and owned a multimillion dollar electrical contracting company. I know how to read electrical, mechanical and other construction drawings. I defiantly do not know automobile wiring and system operations like you car experts. The Jaguar drawings are very basic drawings and show you approximately where the ends of the cables are, junction points and wire colors. I know most wiring failures are at the connection point and the faults are fairly easy to locate. However if there is a boken, pinched or grounded wire is in the middle of a cable run it can be extremely difficult to locate if you do not know what cable harness the faulty wire is in and the routing of the harness it could be impossible to locate the fault so you would need to run a new wire to correct the issue. There has to be a list of harness with identification numbers that lists all of the wires, colors and devices the wires go to to be able to purchase new harnesses or trace wires.

I had to install a new Bosh alternator it is not putting out voltage to charge the battery. The new alternator was installed and wired the same as the old Bosh alternator with the built in voltage regulator and connected to the external voltage regulator dump module. I know several owners have eliminated the load dump module. I tested the system with and without the module with no difference in the charging of the battery. The car does not go through the normal startup sequence where the warning lights come on and turn off if the system is working properly. I located the 100 ohm resistor for the alternator warning light as shown in Fig 2.2 and inserted an external incandescent warning lamp outside the dashboard warning lamps into the wiring circuit. The lamp worked. I started the car the warning lamp for the alternator came on and went off when the car was running. Still the alternator was not producing a charging voltage of approximately 13.5v. The car voltage stayed at 12.4 volts and continued to drop as the load increased and did not change when the accelerator was pressed. What is my system missing to get the alternator to provide the charging output? If I remember correctly I connected an LED lamp load to the alternator terminal D+ and the lamp would not light even after I changed polarity. I did install an incandescent lamp at the alternator from terminal D+ and ground, the lamp stayed lit and the alternator was putting out a few more amps when the accelerator was pushed. Does some type of load need to be added to terminal D+ to get the alternator to work?

I also need to get the warning lights to come on and go off once the car starts and the systems are working.

 

Welcome to Lucas Electric.

The Jag is a wonderful* car hobbled by an abysmal electrical system.

*Except rear brake calipers accessibility and aux air valve design.

Doug

 

Two of three are corrected on my '95 6.0, namely the electrical system, and brakes. They went to modern electric connectors and decent switchgear on the late facelifts which fixed most earlier issues, and also went to outboard rear brakes. The AAV remains, but aftrrmarket rebuild kits are available. I wish they'd gone to an electric AAV.

One additional Achilles heel never corrected on the V12 XJS was the distributor based ignition. The very late 6.0 XJ sedans got a complete new Nippon Denso injection system with coil packs. I wish we'd gotten that.

 

Quote:

I did install an incandescent lamp at the alternator from terminal D+ and ground, the lamp stayed lit and the alternator was putting out a few more amps when the accelerator was pushed. Does some type of load need to be added to terminal D+ to get the alternator to work?

Curious as to what happens if you wire your bulb from D+ to 12v+? This would mimic the instrument panel warning light circuit but eliminate possible harness faults.

Anyhow, I'm not aware of anything unique needed. The warning light bulb in the dash, and the resistor to back it up, provide the necessary resistance to excite the charging circuit. I'm wondering if you got a dud alternator. I'd be tempted to bench test it although I know removal isn't a 5 minute thing.

Cheers
DD

 

Oh, come on ! It ain't that bad ! . Spend some time cleaning grounds and connectors and you've solved 80% of the ballyhooed "Prince of Darkness" problems ! Easy stuff. The non-sealed connectors are the great failing, alas.


Just toss the AAV over the hedge and do without.

Nothin' you can do about the rear brakes, though. Well, unless you wanna convert to the outboard style, which some have done.

Cheers
DD