Hi Jag Lovers

I spent all yesterday evening reading the various posts and variants of rear side lights/running lights disappearing. That happened to me yesterday . . . and I am becoming fearful I've got a ton of trouble. I'm just wondering if there is a basic set of procedures/checks to go through.

My circumstances are that . . . 1) I have never (in the two years of ownership) left the "cruise control" center console switch on . . . because I live in the UK and it rare to get even 30 seconds driving without some obstacle appearing. 2) I rarely drive at night (just prefer not to) and I've never left the "auto-lights" switch on. 3) I have had an intermittent "check rear lights" warning come on only when braking and sure enough the left side (in UK - passenger side) brake light was out. Other side brake light and high (rear windscreen mount) brake light always working.

First time I changed the dual filament bulb . . . problem went away for a few weeks . . second time just cleaned and re-seated bulb contacts . . most times . . . I've ignored it and it went away of its own accord. Seemed to appear after wet conditions (we get a lot of that here!!) . . so assumed it was a bad earth or something like.

Strangely enough I did put the "cruise control" switch on (just to see if it still light up) and I did move the lighting stalk through to "Auto-lights" . . (although its back to off now) a couple of days ago. Yesterday the "check rear lights" warning came on . . but this time . . . both side lights out. All other rear lights (x3 brakes, x2 indicators, x2 reverse lights and x2 number plate lights and even boot (trunk) lights) working fine.

Does this sound like the dreaded green wire on the back of the indicator stalk?? Any pointers would be greatly appreciated.

Fretful Stoke Jag Dude

 

There is a wiring guide I made for the brake light to give you the big picture

notice they didn't make it easy

You can take this doc on a flash drive to the office supplies stores and can print any size and even laminate it

 

Notice , I did previously mark the print as running , this has to do with the rear tail lights as I was working with someone else in the past and saved my print

Notice the trunk fuse box as the yellow square involving both a fuse and relay , you can place your finger on the relay and feel it click closed

 

Most of the trunk wiring runs under the right side rear trunk (boot) hinge and sometimes these wires will break after repeated trunk opening and closing. You will need to pull off the plastic cover to access the wires. I'd check that before I went into some long diagnosis (which I did) on my son's 1999 XJ8 only to finally figure out it was broken wires. Soldered, heat shrink, now all working again!

 

Same issue in my first XJ8: boot open over and over. Frayed wire along the trunk hinge, as Dave noted above.

 

I was also going to say check the wiring on the boot hinge as I’ve had failures there also. Sometimes wires can get caught in the hinge or gas strut and become damaged, it’s worth exploring as a potential easy fix.

 

Hi Jag Folk and a massive thank you for all the suggestions

In short . . I got lucky with this one. First the battery came out and I gave it a good 24hrs charge. I only do shortish driving and battery never really gets a good charge. Whilst battery was cooking inside, checked the wiring running ‘round the hinge strut and found nothing amiss. After cleaned up all bulb contacts and invested in x2 new dual filament bulbs . . I put her all back together and whey hey . . success!! Both sides brakes and side lights/running lights back as they should be.



Looking at the offending bulbs both looked fine. But with my superspecs on . . I could see both filaments running beyond their mount posts and “resting” on the contacts. I should say that I’d switched the sides of each bulb to see if it was the bulb mounts . . and it was after this that the side lights disappeared.

So she was actually doing the right this telling me to “check rear lights”. I could have driven ‘round for months without noticing no rear side lights, as I generally only do day-time driving.

I’ll take that . . . not too weird I suppose to find x2 dodgy bulbs I same pack. Again, cheers for all the helpful pointers.

Stoke Jag Dude

 

I like to check new bulbs by an independent electrical source before I install
them in the socket. That allows some assuredness that the socket/wiring is
the source if all is not well.