Unhappy Well, doh... wiring harness goof upI'm concerned that this may be too specific, but I though I'd start here, as it relates to continuity testing and wiring identification that's not covered in any manual or online source that I've found.

Had to pull the headliner on my 2016 XE because it was falling down anyway. Lo & behold, before it would drop, I had to deal with three wiring bundles holding it to the roof. This one's at the passenger side going back down into the front pillar.

So, we cut them, thinking "No biggie. They're color coded. We'll splice them when reinstalling". Well and good, except the bundle coming up the front passenger pylon, when we unwrapped the sticky tape, has NINE wires all the same... looking to be about 16 gauge and all black. Tried finding a wiring harness diagram online. No luck so far. Any thoughts on IDing unmarked wires, or multiple wires in the same bundle?



So, any suggestions on how to match halves back correctly? Or, how to run a continuity test on each one (to where?)? My first time posting, although I've perused the site for years.

 

You are going to need a full manual with wiring diagrams for this one. They are sometimes available on line I paid $20 something for mine. I believe they are specific to your equipment (year, engine, fuel etc)...

 

Have one. It's massive. I'm in the process of breaking out the electrical section to a smaller file, to make it easier to search. It's still 8 MB. LOL

I'll need a better combo meter. It'll be fun.

Thanks for the suggestion, tho.

 

BTW --

I did put a meter on the bundle yesterday. One's giving me a benchmark ground reading, and one is giving me a residual 3v DC reading. The others are less than 1 ohm.

 

You may be able to shrink the problem a bit IF it goes to say the rear fuse box (in the trunk). You could try continuity from each fuse to the wires heading that way and label them. If you have success with one side of the bundle It may help you with a similar approach on the other side and the switches etc.

This may be helpful...


Good luck!!!!!!!!

 

Excellent source. THANK YOU! Question:

It's powered down. Have you ever just jumped from the colored line to the ground somewhere in the circuit (on either side of the break), to check continuity?

 

If I understand what your suggesting, no I haven't. The electronics on our Jag are mind numbingly expensive so caution.

My thinking is by mapping the cut wires to a fuse box, you will know what they do. You can then go after the other half and understand that. Lets say one of the wires goes to a light fuse in the fuse box, you should then be able to go to the switch and find the wire with continuity there. Now you have a potential match!

 

"potential"

Better than "no", but not quite "probable" LOL

Seriously, tho... Thanks for the insights.

 

This may not be worth the effort, but…
I have wiring diagrams and harness pinouts that I downloaded, but the HTML links are broken. The actual pictures and documents are in subfolders. If you could figure out the names of the harnesses running through the area, you may be able to find the right document. (There are over 1000 )
https://www.dropbox.com/scl/fo/3o2g1...=vgzw4y2d&dl=0

 

Thanks for the 'leads' lol

I've been going through each harness and connection in the front. Thus far, the only challenge has been with the grounds going from the headliner to the passenger side pillow. However, they all seem to run into one block at the upper console (out of 6 blocks, the 17 pin).

So this narrows the challenge a tad.

Now, it has me wondering if 'a ground is a ground... is a ground'... in essence, if they all go to ground, what does it matter? (question pondered jsut prior to the explosion lol)

So, now I believe I've narrowed the question to the black wires running between the grounding block from the upper console, down into the passenger-

side pillar.

BTW--the line that gave me 3v DC a couple of weeks back? None of them are giving a DC reading. I suspect it was bleed from a capacitor or such, that's finally emptied.

 

How goes it???!?!?!?!

 

((((Pistol to head LOL)))

Not having a lot of luck with the fuse blocks (can't get into the trunk now, even with a jump). I'm down to 8 unidentified wires going/coming to/from the passenger pillow. Mysteriously, when I ground my ohm meter to one of the galvanized fasteners on some of the roof hardware:

5 of them give me a resistance reading of .83 ohms
2 of them give me a positive ground reading (0 ohms), and
1 of them still give me a 3v dc reading, even tho it's another black wire -- thinking maybe it's to a battery-backed diagnostic circuit.

The wires themselves all measure, size-wise, about the same (about 18 ga) and look the same anyway, so a visual match seems to be out of the question. Given the other wires in the harnesses, they're probably all on a 10 amp or less fuse.

I'm real nervous about trying them one at a time, especially with the 3v one in the mix. I'll see if I can find it in the shop manual's schematics...

 

Trunks have interior release cables as a safety feature (see pictures). If you have the rear armrest you can open it and with some gymnastics open the trunk.

 

Found it!
You meant to state 'weight loss program' instead of 'gymnastics'?
BTW-put a msg into Jag/Jacksonville to see if I could get a map of the wiring between the overhead console and the right front pillar.

 

You and me both! If they send you anything please share...

 

Just to add to the fun --

Tried opening the trunk a couple of days ago. Didn't 'pop' this time.
Put the jump starter/charger (10 amp) on the terminals in the engine compartment, and tried again. Didn't 'pop' open. Tried driver's trunk release button in cabin. Same thing. Not even noise.
Had wifey go thru the passenger pass-thru and pull the escape tab. Pulled so many time, and so hard, it started to break apart. The wire and a piece of the tab is still there, tho.
Tried prying around either side of the lid striker with a long screwdriver (as far as I could reach in). Couldn't loosen anything.
So, now it appears I'm locked out of the trunk.
What's the least expensive way to open it? Any ideas?

BTW--moved the headliner to the TOP of the car, in anticipation of circuit testing. I've got some Cat 5 wire and mini-gator clips for that...
BTW2--called a couple of dealerships about getting help for finding the end points/terminals for the unmarked ground lines. I believe I'm now in their drawing for the "Joke Call of the Week"...

 

Well.... I have no idea why the manual trunk release isn't working.

I would guess that the wires cut include the trunk release. I think it would be possible to energize that circuit. So if you can verify that none of the wires going into the trunk are grounded and are not tied together, you could try putting 12v on each, one at a time and see if it works the trunk lid, There is real danger here in that if some of the circuits are for lower voltage it could fry something.

Hopefully, someone who understands the electrical of the car better than me will chime in.....

 

Saturday (Episode 12)

I've been scratching my head the past couple of days, trying to figure out how to release the trunk lid. I was giving serious thought to cutting the lid latch with a Dremel. I knew (or seriously thought) I'd seen an illustration somewhere about the rear seat backs folding down, as a pass thru from the trunk space. I thought "Well, one more look-see", and stuck my head (and a brighter lamp) into the trunk from the drop-down armrest between the seatbacks. Using a mirror, I examined the upper-front of the trunk compartment, and saw (through one of the holes in the framing) a spring-loaded device attached to an insulated tube. Why would you put a spring-loaded device at the top of the trunk compartment?

I gave it a tug, and one of the seat backs popped loose! These are releases for the seat backs, if so equipped!

Crawling back out, I tried fully lowering the seatback, but it stopped on the front seatback (lowered all the way to provide more clearance to remove the headliner). So, I connected the charger in the engine compartment, and ran the front passenger seatback up some, to make room for the rear seatback. No problem.

"Well dang", I thought. The lower circuit to the seat worked. Maybe... I thought one more "Hail Mary" might be in order (I know--the definition of "insanity"), so I grabbed the key fob and punched the trunk release button.

The trunk pops open, like it had totally forgotten it had been ignoring me all week. Mind you, I've punched that release button on both fobs about 60 times in the past two-three days. Nada...

So, now I have clear access to the trunk space (and fuse boxes). And, oh BTW--the lock won't open again. Go figure...

Am still waiting on a couple of Jag dealerships to get back with me, to provide guidance on tracing those eight unmarked black wires.

The rear passenger seatback release is hidden in the trunk

Those two foam-wrapped cables in the upper part of the trunk directly behind the passenger seatbacks release them. They're tucked away inside the framing, inside those holes.

Only ONE bleeding elbow today!

 

And, this is the ONLY way I can think of to R&R the circuitry properly--put everything back together and test out the circuits. Problem is, you put the headliner back into the car and hook all wires (except the unmarked grounds) you're still in the same position of not knowing until afterwards.

All that 6 mil on top of the car? The headliner's wrapped in it. I'm reconnecting all the wiring via jumpers, and am awaiting ending point information from the dealer on the ground connections.

The theory is I can get things properly routed, test everything on the car for same, and then put it all back together (sans jumpers) inside later.

That's the theory, anyway...

 

Well that looks like a production! Has any of the dealerships said they WILL get back to you!?!?!? You may have to go to one of them and bleed on an Land Rover! LOL