OK, so I'm ready to start my long process of building a new harness for my 1996 Jaguar XJS. I pulled a harness off of a 1995 car with a LHE3340BE. The latest part number for my car was LHE3340BG, I don't know what the difference is, but I will try to find out before I start by double checking all connections to make sure they match.

So far, the only thing I noticed on the harness I took off was that there was a ground point at Coil #1 that my car doesn't have. It doesn't show up on the electrical diagram, however this will serve as a good segue for my question:

What do the circles and dotted lines mean in the wiring diagram? I've attached it for reference. For example, if you look at the Crankshaft Position Sensor, you'll note two circles with dotted lines heading for another set of circles at LI189-23 and LI189-26. What does this mean?

Thanks.

 

It indicates [some form of] shielded wiring.

Cheers
DD

 

I could not find anything obviously unique with that wire, however I have not removed all of the electrical tape and loom. I'm hoping something will appear much more obviously unique once I do that.

Is there a preferred wire I should use when rebuilding these lines? I intend to stick with an 18 gauge wire. I think I will be using SXL wire, but I'd love to know if I should reconsider that.

I did find something unusual that I cannot seem to find on the wire diagram. It's some kind of fuse? I have pictures of it below. What is it, and how would find a suitable replacement. I'm looking to replace all connectors, and I may as well include this as well. Thanks.

 

Hard to say as the plastic sleeve is opaque, but those look like diodes to me

Cheers
DD

 

I stripped off that yellowed plastic sleeve, and it is indeed a diode!

It is IN4006 in case anyone in the future will need to know...

Now, to order a new one....Radio Shack, why did you go out of business!!!*

(*- rhetorical question)

 

Yes, that is a diode off of the secondary air pump connector. The diode is a 3 amp. It's possible that it gives feed back to the ecu. I have an error code P0413 open circuit. I suspect this diode is bad on my 1995 XJS, causing my error code.

 

Is this a 4.0 or 6.0?

 

My signature is set to reveal the AJ16, or 4.0 engine.

I would strongly suggest you create a signature for yourself as well.

 

I use the mobile app. Signatures don't show for anyone.

 

Hi Vee. Shielded as Doug says. The grouping of circles and dotted lines gives the key to how many cores/conductors are grouped within the shielding. Single, twin and quad core are common. If you look to the foot of diagram, you find them bonded to ground via LIS18. It is common that shielding is bonded to ground at one end only and insulated from its neighbours, thus avoiding ground loops.

Do not be tempted to replace with just standard wiring, or even with modern foil tape wound shielding. Insist on finding the braided type with each core and the external braid shield all insulated separately . . . maybe more expensive but essential to prevent RFI in this sensitive (good pun?) region of feeding your ECU accurately.

BTW, don't panic the 1N4006. This bunch of diodes, starting with 1N4001, are as ubiquitous as carrots. Either match the 1N4006 or go higher, not lower. Then again, this is a "non-wear" item so don't be afraid to re-use if you can't replace. Sure they can fail but, if conducting & blocking as they should, they don't "wear out" like light globes, suspension bushes or spark plugs.

Cheers,

Ken

 

The diode is there as spike suppression for relays/vacuum solenoids or anything that switches with a coil, make sure if you install them with the same polarity, ie with the band in the same direction.

Next - the shielded wires and grounding, all shields should only be grounded at ONE end ONLY preferably the ECU end.

Grounds - ALL sensor ground MUST be grounded at the ECU ONLY, do not be tempted to ground in the engine bay or at multiply places, this will cause ground issues.

I'll be rebuilding my harness when my new engine is finished, I plan to remove a lot of engine bay grounds from the harness and have these return back to the ECU end.