Greetings gang!

I was having some problems with my rear tail lights on my 1999 XK8 (it was this way when I bought the car several weeks ago)...took out the 'lamp control' module (in trunk fuse box)...opened it up, and noticed several large resistors fried (along with the circuit board under the resistors).

I replaced 4 of the reisistors with the same value, hard-wired the burnt circut paths...plugged the module back in, and the tail lights worked perfectly for about 2 minutes, then back to the same problem as before.

My 'gut' tells me that maybe a transister or two has actually fried before-hand???

Anyone out there on this forum have a salvaged lamp control module (or knows how to fix it)?

The lamp-control module has the numbers= LJA 2245 AD / 05 8200 00

If so, please contact me at bowmanconsult@Gmail.com

I sure would like to drive this cat at night.

 

I do not know if this was your problem but on my coupe it kept burning bulbs. At the time it was still under warranty and the dealer fixed this issue. I was told that on the 99 Xk's there was a TSB for this issue and the fix was to add a secondary ground from the tail light assembly to the body.

Thats all I know!

 

Daddyo,

That's interesting.

By the time I brought the Jag home, one of the tail lights were already burned out.

I sure would hate to come across a new module and fry it because of a ground fault.

I'll plan on wiring new ground wires before going any further.

Thanks for the 'heads-up'.

 

bowman, get ahold of either jagtechohio or ken@britishparts (members here); they each have access to a salvaged parts supply and stand behind their parts. I bet ken can help you, he's been butchering xk8s for me for a couple years now, I know he's got at least a few he's parting out. Lamp modules, I would assume, are not hot items.

 

Just to keep you updeated on this thread...It took many hours of playing 'search and find' for a short in the wiring (with no avail), and after three...yes three lamp control modules (each one fried while testing), I decided to completely do away with the lamp control module once and for all.

I determined which wire went to what bulb(s), and wired them all directly.

I was going to use separate relays at first, but the more I looked, the more I realized that all of the relays and fuses are connected BEFORE the lamp control module, so by wiring everything directly, I still had full use of the relays and fuses.

It works fantastic!

The only thing I have to contend with now is the "Bulb Failure Rear" message on the dash, which can easily be cleared.

OK...with that being said, does anyone know of a way to outsmart the message from coming up each time I start it?

Thanks in advance!

 

Well I must say you have taken a few bold steps. Wow!

 

According to the wiring diagram for your car, which I believe you have, Rear bulb failure is an SCP message. It is received by the Instrument Pack (INST) and transmitted by the Security and Locking Control Module (SLCM) See Appendix '99 Wiring diagram.

Looking at the SLCM (fig 9.02), there is one line from the lamp control module, which senses bulb failure, to the SLCM. LCM BT18-25 to SLCM BT41-1 (Red) Can't tell what level indicates bulb failure. I would try floating the line first and then grounding it.
I would be hesitant to apply 12v to that pin. The SLCM may not like it.

In other words give the SLCM what it expects when there is no bulb failure.
If you have removed the LCM you have effectively floated the line.

 

Thanks Fred,

I'll give it a try and post my findings.

 

Fred (and all others interested),

I traced the wire on the module plug, grounded it out, and the "Rear Bulb Failure" message does not reappear anymore.

Gotta love that!

Fianlly, no more lamp control module to contend with.

Thanks for your guidance!

 

Kudos to You!

 

Gus,

Kudos coming from you is a true compliment.

It was simply being fed up with enough frustration regarding the lamp module that led me to throw up my hands in surrender and take such drastic action.

Hey...I went on your website and am VERY impressed with your photography.

For those of you out there who havent taken the time to check out http://www.gusglikas.com/ , do so...you'll be surprised by the photography of Gus.

I know I sure am.

 

Lots of good information on Gus's webpage. We've plugged it and linked it on many occasions.

 

Thank You!

 

what wire did you earth out?? Mine has same fault on dash board!! Can't get rid and am now desperate!!

 

Take a look at the plug at your light module identify the ground wire and install a temporary ground on the light module and see if it corrects the problem.

 

Keith,


After I traced everything out and soldered everything direct, I tossed my hand-drawn schematic in the trash, but I'm confident that someone out here on the forum has the answer for you...especially if you're not comfortable using a volt meter.

I removed my tail light just now to take a look. There is a black/salmon wire on side of the plug that goes into the lamp control module, and the wire next to it is red. I know it seems strange for a red wire to be a ground, but I think that's the one that needs to be grounded (don't hold me to it though).

Insuring a good ground connection isn't easy on these cats, so I included a picture of how and where I drilled a hole and added a screw to create a great ground post on the tail light assembly itself. I did the same on both tail light assemblies.

Again, hopefully someone here on the forum can absolutely verify the correct ground wire on the plug for you.

 

Okay i have had the same problem for years, never really bothered me until lately.

I opened my LCM to find charred resistors, after reading your previous post I too removed the LCM and direct wired everything except the WG wire which was the power supply to the LCM and the red wire. Later I saw you grounded the red wire , so I too did that. Now my car wont shift out of Park unless I manually overide it using the plug just above the "2" on the J slotted shifter channel. Today i'm going to try and track a break in my Tag light bulbs wiring, a short in my boot (trunk) interior lights, and maybe figure out what the hell is going on with that security wire...any suggestions?

 

Update...just in case anyone is interested...

Grounding the red wire does eliminate the Rear Bulb Failure error.

You can pull the 5amp fuse that goes to the Lamp Control Module's power supply(WGI think), there's nothing else on that fuse.

Don't mess with the sensor near your Driver's side fuse box! I think it's a velocity sensor or something, it has a soft reset button on top. Mine must have a short or loose connection. I guess I wiggled it when changing a blown 15amp fuse that controls your interior boot lamps, this is what caused my gear shift issue. I disconnected it and the entire car shuts down except electrical functions.

I reconnected it I got EVERY Failure message that has ever been written!

I disconnected the battery, checked the connection, reset the soft button(even though it wasn't tripped) and reconnected everything, now she's perfect again....DON'T MESS WITH THAT SENSOR.

Oh and I found a cut wire for my plate lamps, previous owner's handy work...

 

Hi guys.
I have the same problem! No rear night driving lights or plate lights. Also no front side lights! just taken the LCM out and it has one fried resistor (fried so bad that I can't even read the colours so can't replace!) the one next to it doesn't look pretty but still works.
does anyone happen to know the colour codes to resistors # R1 & R8 ?
if not i'll just buy another LCM. There's one on ebay for £30 (might need it anyway if this doesn't work :-/
Greg

 

I bought another LCM ( after getting messed around by the guy who was supposed to replace the restistor) Fitted it. But the lights still aren't working. although I am now getting 'rear bulb Failure' readout on the dash! hehe.
Not sure what to do now, I guess to bypass the LCM ?