88 jaguar XJ6 left driver side head light and back brake light problem
 

Hey Jaguar lovers i have a question.....I own a 1988 Jaguar xj6 base. My left driver side head light has went out along with my left driver side brake light. My left driver side head light is out but when i turn my bright lights on all my head lights lights up on high beam but when i turn my high beams off i only have one head light that comes on on the passenger side but not on the driver side. I have replaced the bulb on my left brake light and it is still out. I need to know what is the problem with that? I would greatly appreciate it if i can get the solution to my problems ASAP thanks....
JaguarDre

I've moved your question from Jaguar Forums Feedback & Suggestion Centre to XJ40 forum. This is the place to post technicla questions about your model.

Graham

I just got through dealing with a similar problem. My guess is that there's either a voltage supply or grounding issue, although it's possible that the problem is with the bulb failure modules. Do you have much experience working on electrical systems and do you have a volt meter? There are a couple of places where measuring voltage would help to isolate the problem. I had a headlamp that was giving me the same problems recently that I fixed by cleaning the contacts of the fuse box in the center console, but it took me a while to locate the issue. If you can take a couple voltage readings then reading the voltages at the center console fuses 1 and 2 with the key in the ignition and the car on (doesn't have to be running). When you pull the fuses you should be able to read 12V on the side of the fuse holder that's further from the dash. It's an easy place to start, and you don't have to disassemble anything to check.
Hth,
-A

Hi Jaguar Dre,

In addition to Albert's excellent advice, I would recommend that you study the schematics in the Electrical Guide, which you can download here:

Jaguar XJ40 Electrical Guide 1988

The schematics show where you should find battery power with your voltmeter and where you should find continuity to ground. Beginning at the bulb sockets and working your way upstream you should be able to locate the point of failure.

The Bulb Failure Modules (BFMs) and all three fuse boxes are known for poor solder joints that can often be resolved by reflowing the solder and/or supplementing with new solder.

The relays are known to fail, especially the Hella relays with blue snap-on covers.

On our '93, I had recurring trouble with brake and tail lamp bulbs due to the center electrical terminal in the socket losing its spring tension and arcing/oxidizing. With the power off, you can carefully clean the terminal and use some long needle-nose pliers to pull the terminal outward a bit so it applies more pressure to the center terminal of the bulb.

Cheers,

Don

This just happened to me tonight. Once again thanks Don B would love to buy you a couple of pints.

I have checked the the middle console fuse box and all the fuses are still good i tested them with a fuse tester they all arent burnt out and they all are lit up green. I also checked the bulb module to see if the wire harnest connector is bad but i dont think its the problem. My left driver side brake light and head light still doesnt work on low beam(head light). I think it cant be anything major because all 4 headlights work on highbeam but only my One right head light work on low beam. Help!!!! me please...

Checking the fuses alone won't rule out a problem at the fuse box, you need to turn the car on (no need to turn the engine over) and verify that you're getting 12V supplied to the fuse terminal. In my case the fuses were all fine looking too, the problem was that the corrosion on the fuse box connector broke the circuit so the fuse wasn't seeing any voltage to begin with.

The typical problems with the fuse boxes and bulb failure modules (BFMs) are poor solder joints on the circuit boards inside, so an external inspection of the electrical connectors is inconclusive. You have to get inside.

Unfortunately the Jag-Lovers forum is migrating photos to a new server so you can't currently view my large photos, but you can see my thumbnails and descriptions on fuse box problems at this link:

Fuse Box Service

I don't have photos of the BFMs, but the schematics are in the Electrical Guide I previously provided the link for, and it would be worth searching the forum to see if anyone has posted photos of the circuit board.

Cheers,

Don

Resonse to light problem
 

Ok... I have removed the whole center console and cleaned the fuse connector twice inside out with the crc spray. My left rear tail light are now working again but my head left front light is still out.any suggestions?

Pics of the center fuse box console and fuse connectors
 

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https://cimg3.ibsrv.net/gimg/www.jag...f63027af18.jpg
https://cimg4.ibsrv.net/gimg/www.jag...6f4a412062.jpg
https://cimg5.ibsrv.net/gimg/www.jag...19898d4b52.jpg

Problem almost solved
 

Wassup Jaggers!!! I found that my left headlight is working again after changing the whole lamp so that is out the way but the left rear brake light is still out I've been tapping on the left rear brake light and it comes on and it goes out and often does it from time to time as im driving. I then gave the wire connector some play and it comes on and goes out. Im guessing that's where my problem lies either its corrosion in/on the wire connector or it needs to be replaced. Almost certain this is where my problem is but i did say almost so im still searching for the solution. Thanks for the knowledge.

A common issue with the tail lamps of both of our XJ40s was that the center terminals in some of the bulb sockets, which were bent pieces of metal, tended to lose their "spring" and cease to reliably contact the center terminal on the base of the bulb. The intermittent contact with the bulb led to arcing that caused oxidation and made things even worse.

When this would happen, I would remove the bulb panel from the tail lamp and remove the bulb that was exhibiting intermittent operation. With needle nose pliers I would gently pull the center electrode upward to help it make better contact with the bulb. Then I would clean the oxidation with a suitable tool.

My favorite tool for this purpose is a Nick Sander, an ink pen-sized tool with a bundle of glass fibers protruding from the end. It was designed for cleaning rust from nicks in auto paint, but it works great for cleaning oxidation from electrical contacts. Other tools that can work are a small wire brush such as a battery cable terminal brush, the rubber eraser on the end of a pencil, or worse case, a small piece of 800 grit sandpaper glued to the end of a wooden dowel (don't use sandpaper that is any coarser or it will leave scratches deep enough to promote more corrosion).

I hope this helps.

Cheers,

Don