Brand new to Jags and brought home my 1998 XJ8 on Friday. The trunk lights do not come on despite both bulbs being fine. Does anyone know whether there is a mercury switch controlling them or a standard switch. Regardless of which type, where is it? Funny enough, I couldn't find a fuse labeled trunk lights and every other light in the car works properly.

Any pointers will be appreciated.

Thank you.

 

The wires on the loom along the trunk hinge are known to fail because of the movement of the trunk - the flexing snaps the wires. Look on the right hinge.

Are you getting the warning on the dash that the trunk is open - that will tell you if the switch is working ........... or connected

 

Thanks for the response. That makes sense, but none of the warning lights are on showing the trunk is open. Do you know what kind of switch is used?

 

I have never had this problem with any of my Jags -- so I have never searched for the switch. Normally they are in the lock as mercury is no longer acceptable in switches -- I believe any use of mercury in a car is banned?

But I believe you will find a wire problem in the loom.

I do not know for sure if the output from the trunk switch powers the trunk lights directly and also sends a signal to the BCM to illuminate the dash warning "boot open" or if the trunk switch sends a signal to the BCM and then the BCM lights the trunk and also send the signal to the instrument cluster to warn about the open trunk. Most items in the Jaguar are the latter.

Nothing is simple with the wiring in a Jaguar -- or any modern car for that matter. Most people who have no trunk lights with no dash warning have a broken wire on the trunk hinge.

Its better to get nothing -- as the other often points to the BCM ....$$$$

 

the normally open microswitch is attached to the side of the latch inside the trunk lid. And Mercury is used in HID headlights to this day
But like Yelt said you more than likely have broken wirs inside the harness at the right trunk hinge. Its very common

 

i have this same problem, no trunk lights and no "trunk open" message on the dash. The wires look good, but guess I should look harder. Any ideas on what color wire it is?

 

Thanks guys, I will advise after taking the loom apart.

 

its the "broke in 2 color"

 

thanks smarty pants, color me amused

 

Here's a diagram and colour codes for the wiring your looking at. I had the same problem with my boot lights, when i inspected the cables they looked fine, separated them out and gave each cable a tug and the wire was broken inside the insulation, so I could feel the broken cables stretch.

 

well everyone seems to think i have wiring diagrams and check engine lights codes in my head so thats the best i could do at the time, and your welcome, but really when you open the harness up youll find the wires broken if thats the issue

 

yeah, i was just joking...thanks to everyone for the info though!! I'll fix this darn thing yet!

 

I had same prob. Open the loom at the hinge and separate the wires. Ive forgotten the color, but if you'll take each wire between your fingers and bend it slightly along the length of the hinge area, you'll discover a wire that bends more easily at one point. That's yer busted one. Suggest soldering it and heat-shrinking tube the repair.
Best, smagl

 

and how would you explain the use of NiMH batteries in electric vehicles?

 

Don't mean to be a smarty-pants, but from Wikipedia -

A nickel-metal hydride cell, abbreviated NiMH, is a type of rechargeable battery similar to the nickel-cadmium cell. The NiMH battery uses a hydrogen-absorbing alloy for the negative electrode instead of cadmium. As in NiCd cells, the positive electrode is nickel oxyhydroxide (NiOOH). A NiMH battery can have two to three times the capacity of an equivalent size nickel-cadmium battery. Compared to the lithium-ion cell, the volumetric energy density is similar but self-discharge is higher. (Compare: low self-discharge NiMH battery)

 

Hi there,
Rather new in Jaguar and on this forum.
I had the same problem; no lights no message.
The fastest way to check for busted wires is to short circuit the switch for the lights: This switch is located in the top lid of your trunk at the lock itself. Remove the plastic pins, closest to and around the lock, wich holds the lid fabric. Behind this fabric there is a black plastic connector with two wires. One end goes to the switch and the other end will go into the wire loom. When you put a small piece of copper wiring approx. 0.5 mm2 into the connector part with the contact bushings, you will do the same as the original switch will do. There is no risk for damaging any fuse or so. A switch is in fact a short circuit maker. When you connect the two bushings the lights must go on when your wiring is okay. Is there no light or message on the display you will have a wiring problem.
The connector part with the pins is in fact the switch wiring.Using a digital multimeter you can test the switch for proper working. This switch has Jaguar number LNC6242AA ( in my case) for a 1998 Jaguar XJ8.

Hope this will work for you too.
In my case the switch was broken.

Job.

 

Old thread, I know, but I just created an account to say thanks, and to add a little further info.

I had the exact issue described here. First thing I did was to remove the bulbs and test. Checked continuity, fine, so then I decided to actually test from a power source, and they lit up, so all good there.

Next, as described above, and as a result of a wiring diagram I found elsewhere, but I see it is also posted here, I checked for 12V at the lamp connector, because it is the ground wire that is switched, so the 12V should be present. I had 12V, so no need to check out the wiring harness. Good news.

I then took out the two bolts that hold the plastic housing in place, and then realised I would have to remove the lining, which required only 4 of the little press in plastic plugs to be popped out. I'm sure there will be a tool, but managed quite well with a flat blade screwdriver, and my fingers. Once those were out, the liner just hung down a few inches, sufficient to get at everything I needed. I found a clip holding a connector for the switch, in the lid, and teased it free, and disconnected it. Exactly as described above, shorting out the two female parts, with a short bent piece of 0.5mm solid copper wire, which I got from the earth in some cable I had I the garage, made the lights come on. Tested the switch with a multi-meter, at the male plug end, on the two pins in there, and it worked, of a fashion. It tripped my diode test on the meter, so it beeped, but when I checked for a resistance reading, I was getting 700 ohms, or so. Open circuit when depressed, but when released, a high reading.

So, how to get the switch off? I looked and looked for videos, but in the end, having found nothing, I just set about it. Take the third bolt out, which holds the mechanism in place, which has now been revealed by moving the liner, and slide the mechanism out a little. Just a couple on inches, and all your hooks and the like will stay in place. I then got my head torch, and second pair of glasses, to study how it clipped on. It is a hook at one end, by the plunger, and a clip in the middle of the switch. All you need to do is push the little clip with a small flat blade screwdriver, and it will come free in the middle. Once free, the hook end can be wiggled off, and is helped by depressing the plunger fully in.

I then threaded the wire and coupler out, and I had the switch in my hand. Tested it further, but always with a high resistance reading. I then thought, well, I'm going to need another switch, if I can't repair it, so again, I just set about it. The Jaguar plastic parts surrounding the micro switch easily clip off. Two clips on the side, and two at the end. I used a small sharp modelling knife to flick them up. When the switch came apart, there was a nice little micro switch inside, made by Cherry. I didn't want to buy the full Jaguar part, because it was sixty odd pounds, outrageous by the way, but anyway, if I have to I have to. Now though, I had the little micro switch in my hand and tried to clean it with contact cleaner. It is a sealed unit, and the tiny plunger has a sealing boot around it, so I wasn't convinced I was having any effect. Anyway, the readings came down, and at one point I had them down to 3 ohms, but still it should be 0.1, or close, which is the reading I get when I just touch my leads together, and it still didn't work the lights.

Thinking, I have nothing to lose, I cut the tiny boot off with a modelling knife, and sprayed and sprayed with my contact cleaner. Nothing, indeed, oddly, the reading went up. Anyway, again, I thought nothing to lose, maybe there is a piece of crud stuck in there, so I just whacked it hard on the bench, swinging it by the end of the wire. Just one good bang, and measured it again. I couldn't believe it, 0.1 ohms. Tried it dozens and dozens of time in a row, and every time it read 0.1 ohms. Took it to the car, plugged it in, and boom, the lights were on.

Following the reverse process for assembly was simple, and then I did one final test to make sure they were off when the boot was closed, by making a video with my phone, inside the luggage compartment and reviewing it afterwards. Did it several times, just to be certain they always went off, and there was no issue.

Okay, so the teeny tiny boot is missing, and the micro switch may fail again, but it is inside the plastic parts from Jaguar and I suspect it may well last a long time. The car is 23 years old, and around the mechanism was pristine, and the switch itself was super clean, as was the outside of the Jaguar housing with the part numbers on it, so I think it may well be fine. If not, I now know how to do it anyway. You can actually see one of the side clips and the two end clips, that allows you to open the switch up, to get at the cherry microswitch inside on the picture below. I'm sorry now that it's the only photo that I took during the process, but I only did that to get the part number to check availability. Maybe that Cherry part number would allow the microswitch to be sourced cheaper? Don't know, but I'm happy I found this thread, and other similar references online, to give me the guidance I needed.

Thanks to all who contributed.


Clear markings

 

Darn. My trunk lights work intermittently, and I always just assumed it was caused by broken wires running back past the boot hinge, but maybe it's the switch itself...
I JUST placed and order with SNG Barratt too Oh well, I'll add one to my cart and get it next time

 

Having same problem, wires look ok no rubbings to the eye. Can you by pass the micro switch?

 

Hmmmm, sounds like the moral of this story is....
If it don't work bang it.