I have a 2003 XJ8.
A couple of months ago I had an issue where the passenger side brake light stayed on. I bypassed the security module and ran the brake lights off of one wire as seen in this video.
Everything was working fine until last week. Last week both brake lights stayed on constantly, I drove it for a couple of days and was just removing the bulb when I shut the car off. Now the brake lights will not even come on.

I bought a new brake light switch and plugged it up to test the lights, they still do not work. The bulbs are not blown, all other lights work fine, cruise control works fine. The middle light (in the rear window) works fine.

Does anyone know what the issue could be, and possibly an easy way to fix it. Would it work by running all 3 lights off of the wire to the 3rd light? Any suggestions?

 

I just had a very similar problem on my 2002 XJR. Passenger side brake light would not work (n 12V through the harness) and the driver side would stay on sometimes. I just wired both low brake lights to the relay controlled 3rd brake light to take the module out of the equation. Check my post history over the last week or so; someone posted the schematic in my thread so you can look for the right wires at the trailer connector. Even though the schematic is for a 2002 the wires weren’t all correct, but you can use it and a DMM to figure out which is which.

Mike

 

Here is the link to my story:
https://www.jaguarforums.com/forum/x...roblem-120667/

I am sure it will work if you run all three lights from the middle one, you can connect your lights to trailer connector in the trunk(middle light is fed from the same relay as the trailer light).

Surprisingly you are not saying that you are getting "check rear light" warning, you problem may be an easier fix than replacing chips in SLCM.

Good luck.

 

Thanks to both of you for responding. Yes I am getting the check rear lights error, I forgot to mention that.

 

What do you guys mean by trailer connector?
Also, do you know where the exact fuses are for the brake lights? I looked at all of the single fuses in the truck area, none looked bad.

 

In my link there is a picture of it, yellow connector. On my car it was under the SLCM (which is under the fuses in the trunk).


For the left/right break lights there are no dedicated fuses, they are powered via SLCM (via chips that should act like relays, but they seem to burn like fuses).

 

I looked at your picture, but how do I find which wire to use?
I don't understand what the schematics or how to find a pin or anything like that. Is there a simple way to let me know exactly what to do? Such as "use the blue wire from the left brake light and splice it with the yellow wire coming from the 3rd cluster of wires" or something simple like that because otherwise I have no way of doing what should be done.

I found the yellow connector, so I should just use the wire I spliced and run it into the connector on the side with the 2 wires?

 

If you look at the picture, you will see the connector plugged into SLCM. The third wire from right in top row is connected to passenger stop light. So I cut it from SLCM (you can see there is a bunch of electric tape where I cut it off) and then connected that wire into pin 7 of the yellow trailer connector (I had to use a piece of white wire as an extension). If you do the same that will make passenger stop light work.


To make driver side light work as well, I would cut from SLCM the wire connected to driver side stop light and also connect it the same way to pin 7 of the trailer connector. I do not know by memory which wire is going to driver side stop light, but I can find the schema tonight when I get I home.


If you do this, the wiring you did before is not needed.


I feel a bit uncomfortable suggesting this if you do not understand schematics and can't identify pins by number. It may lead to mistake and make things worse. (I will lookup pin/wire for driver side light anyway.)

 

Ok, attached is the schema. In red color I draw what I am suggesting, "x" means "cut".


Driver side stop lamp is on pin 9. Pin layout is attached as well, pins 3 an 9 circled.


So my suggestion(as a temporary solution) is to cut stop lamp wires (connected to pins 3 and 9) , screw them together with some piece of thicker wire, and than stick that thicker wire as pin 7 into trailer connector.


I could not find trailer connector layout, but according to schema it should be orange color wire. If I am not mistaken there is a number printed on the connector. You should have no problems finding it.


As a long term solution I replaced those chips inside SLCM module, it worked for me as well as for a number of folks here. Chances are it will work for you too ( But of course that requires ordering those chips and some soldering skills ).


Hope that helps.

 

This is what I did also. You should really use a voltmeter to make sure you are cutting and tying the correct wires together. My wire colors didn’t all match the schematic for the 2002 cars for some reason.

I put connectors in the wires so I could put them back to stock when (if? lol) I get around to fixing the chip(s) in the SLCM. Then I made a new harness tying the brake lights to the trailer brake light that I plugged in.

Mike

 

When I did this bypass, I thought to leave it there for years. But that "Check rear lights" message was very annoying. Replacing chips turned out to be cheap and relatively easy exercise.

 

I don't know how long running BOTH brake lights from a single semiconductor will last.
If the semiconductor failed while powering ONE lamp, I think that TWO will draw more current and cause the remaining one to fail??????

I would trust powering them (brake lights) from the HMSL relay. The relay can handle lots of current.

Just a thought.

bob gauff

 

Exactly, and this suggestion is about running both lights from relay #5 (the one that is designed to power all stop lights on a trailer when attached).

 

So just so I'm clear. I need to cut the wire that goes to the brakes, combine them and connect them to the trailer light.
The left is in pin 9, the right is pin 3, they need to go to pin 7 in the yellow box (that has an orange and green wire sticking out of the top, like the one in your picture).

How do I know what pin is what? There are no numbers anywhere. I see the lines in the schematic but how do I find them in the car? I'm guessing pin 7 is the empty corner one near the green wires. If I'm using the wire I've already got from the actual brake lights then I should just run it into the slot pin 7 correct?

 

Yes, cut the brake wires at the lights, tie them together, cut the brake wire at the trailer connector and run that wire to the 2 wires you tied together from the brake lights.

Ideally you’d use a meter and check each wire at the connector to the light. You should be able to check each wire and find which goes +12V when you turn on the tail lights, fog lights, reverse lights, turn signals. Which ever is left is the brakes. You could also pull the light housing out of the car and use a meter to check continuity between the contacts in the bulb bases to the pins in the connector to figure out which wire is the brake light.

You do the same thing with the trailer connector; find out which wire goes +12V when you press the brake pedal.

I can try to get some pics of which wires I cut/added connectors to this weekend, but I can’t guarantee your wire positions will match mine. The only way to really know is to use a meter.

Mike

 

All that you said sounds right to me. Pin 7 is in the corner next to green wires. An yes, instead of cutting pins 3 and 9 from SLCM you can simply take wire you already got from actual brake lamp and insert it as pin 7 into yellow trailer connector.

 

Some of these steps may help me found out why my Right License Plate Bulb does not work. This was going on when my right brake light wasn't working, the dealer's mechanic fixed the right brake light but didn't repair the license plate light. The bulb is good in the holder and even tried other bulbs and it will not work. Anybody ever had found out what wire is involved?

 

I recently purchased a 2002 XJ8, a month later I stated having intermitting brake light (passenger break light). The check rear lights alarm comes on every now and then the bulbs and fused are good. Since I am new to Jaguar cars does anyone have an idea of the cause of this problem (could it be a relay or brake peddle switch.


please advice
ramlyd2

 

Most likely Security Locking and Control Module is bad: do a Google search or search this forum, there is more than just this thread that describes the fixes. OBTW, Robert later found that his repair in the YouTube video was a bad choice -- as Bob pointed out.