Third stop light not working
 

hi to all

my third stop light in the spoiler is not working anymore, anyone having this problem? is it the whole led that is dead ?
all other trunk lignts camera etc are working

thanks for your help

All LED's don't failed at once! it means no 12V's ; check ground, connectors or wiring. Don't think there is a separate fuse for this light unit.

Cheers, Adrian

i checked everything, all seems to be connected. i saw a grey unit where the black small wire goes, could it be this that is dead? impossible that all led dies ?
thanks

I've had a look at the wiring diagram, and there's something called "Suppressor-stop lamp- High mounted" that is connected in parallel with the LEDs. Perhaps that's the grey unit you're referring to - it should be on the LH side of the luggage compartment behind the carpet. The brown/red power wire that feeds the LEDs and the black/green earth wire also connect to the suppressor.

Yes this is the part i'm talking about, i disconnected it and reconnected. I will test if there is electricity passig throught these wires tomorow, and will remove the spoiler to see if the wire is not cut.

I'm not 100% sure what is inside the suppressor - the wiring diagram shows what appears to be a capacitor. I wonder if the fault might be in the suppressor - perhaps you could try disconnecting it and see if the LEDs work when it is not in the circuit. If they do, you need a new suppressor.

https://cimg4.ibsrv.net/gimg/www.jag...3c3775aefe.jpg


Here is the piece, what to do next?

No, that's the AM/FM amplifier (I checked by searching for "18C847"). I'm not sure what the part number for the suppressor is - it may even be included in the stop-light part.

Way old thread.
The part number for the suppressor is 9W8318K891BA. It's integral with the short harness that goes from the spoiler light disconnect and is about 12 inches in length. The suppressor does have a capacitor in it, but it's integrated into a circuit board with many components.
Mine is dead, hence no CHMSL. I've tried a web search and no luck. I also have a parts request into the "local" (60+ miles) Jaguar Dealer Parts Desk, but no reply yet.

From what I've read the capacitor is only used to prevent popping on the audio system - an open cap would not prevent the light from working from what I can see - if its shorted circuit then the led's are effectively short out which would probably blow a fuse.



https://cimg3.ibsrv.net/gimg/www.jag...bca34b370b.jpg

That's the same schematic I used.
Anyway, there is a lot more stuff in that Suppressor than a capacitor:
https://cimg8.ibsrv.net/gimg/www.jag...0ec1938d25.jpg

There is a full 12V into this harness, but only 1.32V come out. This is weird, since the harness is in parallel. That's the way it is though.
The LED array works fine as I put 9V into it with a dry cell and LIGHT.

I was thinking maybe leave out the suppressor and add a big-ass resistor in Series between that 12v connector and the light array. It'd suck to burn something out though, like a chassis module or something.

Yer getting some where - I can't make out that black looking unit could it be an inline fuse.

I still think that surface mount transistor looking component is not passing current - check for voltage either side with some one holding the brake pedal down.

https://cimg5.ibsrv.net/gimg/www.jag...c2baebd9a7.jpg

The transistor is open both directions. The "Inline Fuse" is just a black wire, for an additional Ground Wire.
Whatever those silver-black things are, (you didn't state) have continuity both ways so clearly not diodes. The tan-silver things are open both directions.
Going by all that, I'd assume the transistor, as you stated.
The capacitor holds and discharges fine also.
The part is removed from the car now, I'll check for voltage when I get a chance.

I mentioned that CJ after I took a look at the two leads going to the same foil on the left side - it may be some kind of zener diode (possibly twinned for current capability) to give some voltage regulation in combination with the silver and black/blue looking resistors.

Or it could be a simple diode combo in a single surface mount package:


https://cimg2.ibsrv.net/gimg/www.jag...3a2ae74ef3.jpg


Brown capacitors are good if open.

Well then, probably that weird diode/transistor thing as full 12v before (which makes sense as it's directly from harness) and zero voltage after at the single post. And since no power past the diode thingy, no power to the capacitor at all. No power TO, then nothing out the negative side and back into the harness.
Seriously though, I don't understand the need for all this nonsense. All that would be needed to ensure the LED array doesn't get overpowered and burn up would be a single resistor, and maybe one diode to prevent feedback. Plus, why the capacitor? What would it power since the brake light gets constant power from the brake pedal circuit? Maybe to stabilize and reduce noise, but I can't see that as a problem.
Sheesh, I don't know.
Anyway, now maybe I should go to Radio Shack and get a diode, pull off that weird thing, resolder the diode in that spot and hope stuff works.
Thanks for the help, McJag

I'd probably try a diode as well CJ

Radio shack carry 1N4001 to 4006 - all are 1 amp rated (I figure that should be adequate for led's - all of them are rated at well above 12 volts - I generally have a few 1N4004's hanging around)

Not sure if you know the correct polarity:

https://cimg6.ibsrv.net/gimg/www.jag...c8444f2598.jpg

Well, that's not true. The brake lights actually get a pulsing power signal. So the capacitor is to smooth it out so your lights don't flicker.
When I upgraded my 07 XK to have LED taillights, I had to add some circuitry to do that, as the original incandescent lamps would absorb the pulses via the lamp filaments and you wouldn't see the flicker.

Problem is, those 3-pin diode packages come in all flavours:

https://cimg2.ibsrv.net/gimg/www.jag...ba048c6208.jpg

So, hard to tell which one you have, if it's open-circuit between all pin pairings and in all directions. But you do need to test between each pair and with both polarities to be sure.

Time to dig out the super strong magnifying glass, to see if there is any sort of marking on it (it would suck if it were marked on the bottom).

Going by the way it's set up on the board, it would have to be BAR 15-1. Pin 1 and 2 are on the same circuit, and pin 3 needs to be the output.
Using my handy Phone App.....

https://cimg3.ibsrv.net/gimg/www.jag...abbd930a14.jpg

Just did a quick search for surface mount diodes with the JA marking - a number came up:

I think Jag is using a similar package and paralleling the diodes for increased current capability:

Example:

Notice where it says "marking" BAV74 JA



https://cimg9.ibsrv.net/gimg/www.jag...d552c04918.jpg

Yep, that seems to be the Puppy.
Everywhere I look they are right around 25 cents.... PLUS $3 - 10 shipping.
Guess I go to Radio Shack and buy a Normal Diode for a nickel and see if it works.
Going by the circuit and the PCB, a single larger diode should do exactly what that tiny one does. And it is SERIOUSLY tiny. 1mm X 2.5mm

A regular diode will work fine CJ.

A trip to RS and $2 for two diodes, a few minutes soldering and VOILA; Working CHMSL.
Now I'm glad my local Jag dealer never replied to my inquiries for a new harness. Probably would have been $722.

Right on....:icon_headbang:.....:icon_dance-tap:

I think you should change your profile pic to this CJ;

http://www2.compute.dtu.dk/courses/0...acereading.jpg

In my younger days I could have designed a morse code strobe for the thing and built it out of water heater parts. *sigh* I can't even remember ONE of the color codes for resistors now. Age really sucks.

I've got the color code burned into my brain after years of looking for resistors in cheap mixed bags...my eyes were much better then.

Where is the board located in the car by the way - it may come in handy to know for the future.

Inside the trunk (boot) lid behind the interior panel. It's directly to the left of the FM Signal Amp and connected to the tail of the CHMSL array. The whole thing seriously is less than a foot long from F-conn to M-conn, with 22 gauge wires.

fixed?
 

Get it fixed? I had the same issue with my XKRS; different 3rd brake light but the failure was in the short removable harness (not sold separately). The shop I had it at sourced failed "diode" @ local electronics place in Calgary and they fixed it by soldering in new part. I do not know which item in your photo was the culprit but if I can help, let me know. Could hook you up with name of shop.

Yes,I fixed it. I desoldered that "JAY" deal, then soldered a 12V diode in its place. Everything works wonderfully now. Cost me a buck.

Well done Cee Jay!
So you've still got Radio Shack in your area? They all disappeared from mine a couple of years ago, and I assumed they were totally out of business.

I have one left in a forty mile radius when there used to be seven or more. One was just over a mile from me, now closed. The only one close is now 15 miles.

Yep, used to have one just over a mile from my house as well, and I walked right by the front door twice a day as I walked to and from work. I guess that was part of the problem, I walked right by, rarely ever stopped in, and when I did it was for a small $ purchase, the big stuff I bought elsewhere.
The most I ever bought there was when the store was closing, and I was grabbing as much as I could at 75% off, kind of sad.

OK, bump outta nowhere.

9W83-18K891-BA = C2P20329, parts catalogue calls it "antenna, high mounted stop lamp, positive, radio"

But that is not the Suppressor shown in the wiring diagram paralleled with the high mount stop light, those are p/n C2C41321 or C2C10805.

This part is also used as a noise suppressor in the ignition system in the X350 XJ, the S-Type, and also the XK, under the bonnet.
These suckers;

Attachment 211315

In the XK they are also in the left side of the boot, if you pop out the plastic vent panel you will see it. I've been going through this hell the last few days with my radio reception crapping out...

But for the life of me I have not found this 9W83-18K891-BA / C2P20329 inline in the cable to the centre brake light...

According to the wiring diagram, it is connected in parallel, not in series. It splits off from the brown/red feed to the stoplight at connector CA054 (LH rear), and then connects to ground.

Yeah, this one

Attachment 211316

Is the one in parallel to the brake light.

It's not the one in CeeJays pictures, I can't find that one.

Durrr - that will teach me not to post before reading the entire thread...

It's because they changed the design. The earlier type is the parallel unit we've been discussing. There's a later one, which I've now found in the diagram for VIN 44940 onwards:


https://cimg8.ibsrv.net/gimg/www.jag...3e814835f9.jpg

Is that boxy thing openable to attempt a fix?

Most things are openable, given the application of sufficient impact engineering...

:icon_smash:

On AF aircraft, components like that are filled with "potting compound", a catalyzed goop that completely engulfed the entire circuitry to 100% eliminate any possibility of component movement or environmental contamination. The stuff was nearly impossible to remove. If attempted, the circuitry was destroyed anyway.