That's unusual in civilian applications, other than in security devices or things where the manufacturer is trying to protect their IPR. For normal electronics, it isn't deemed necessary.

do you have a picture of the diode in place

I do not, sorry. Once I put it on I recovered the whole thing with heat shrink.
I can draw a pic if ya want. Hey, I'll photoshop the above to approximate.
BRB

I just soldered the thing from one side to the other, sort of bent over so it wouldn't stick up:

https://cimg7.ibsrv.net/gimg/www.jag...adba24e601.jpg

Now that I look again, I do believe the diode was a fair bit larger than what I depicted in the picture above, but basically it's good for reference.

Where is this little circuit board located! Thanks!

It's integral to the harness up inside the boot lid, connected through the spoiler on the right-hand side. The thing is about the size of a pencil and covered in black heat shrink.

Awesome! Thanks Cee Jay!

It seems that you have to be an electrical engineer to own one of these cars. I can fix almost anything but I am not and it is a bit intimating.
I don't understand why simple things need to be made so complicated.

Don't be one. Bring it to a dealer like 94% of everyone and pay what they ask.

Will the 3rd light work without the suppressor...I hooked the light up to 12 volts and got nothing

...... therein lies your answer.

Dunno - not sure if the feed to the lamp is just plain 12V or whether it's something more exotic, like 5V or even a pulsed signal.

I seem to remember that it is pulsed out of the BCM or something.
I won't even say I am anywhere near sure of that, just some thoughts bouncing around inside my head-bone.

Ditto - I seem to recall that folks trying to get a nice, simple 12V signal out of the reversing LED (to trigger reversing cameras) had some issues because things have moved from electrics to electronics.

I don't see this thing anywhere!!!

viper, you REALLY need to add your vehicle info into your signature. The pre-2010s have a bit different setup than the 2010s and later.

To find it, take off your boot lid liner and reach up inside to where the spoiler is, that is also where the single wire from the Center Brake Light comes through the deck lid. Follow that single wire down and towards the right hand side of the car, to about where the deck lid 'bends' from the top to the back. Maybe about eighteen inches? That wire will go into either the long heat-shrinked thing or into a little box-like thing. It's in a small area and there are a couple things already there and maybe in the way. I think the Radio Antenna connector/converter/whatever is there and in the way. I THINK it's a shiny small metal cube of some sort on a bracket with two bolts/nuts. Just need to move it out of the way to get your hand up there. <-- I seem to remember, but I refuse to guarantee any of this info.

I got nothing don't see anything there that resembles that pencil tube thing or any small square box of that matter just think the 07 through 9 must be totally different

When mine quite working on my 07 I just purchased an new one as I didn't know it could be repaired at the time. As I remember, after the inner boot liner was removed, the hardest part in getting the spoiler off was prying out those little plastic clips that finish where the torx bolts are on the LED light.

Instrucitons are in the workshop manual (pg 2907).

Love to hear more...Are you saying that capacitor thing is inside the spoiler? I just need to know where this piece is located

Many thanks for all the info above, which I have just used to complete a similar fix on my 2012 XKR-S High-level brake light which was not working. It turned out that the diode was effectively short-circuit, so the filter was not doing it's job, which I assume tis top provide a stable voltage from the pulsed control signal. If anyone is interested I replaced with 1N4002 did which has similar voltage characteristics to the BAV74 originally fitted. This seems to be a design fault - perhaps there are voltage spikes, or perhaps the temperature under the boot / trunk lid is excessive. Anyone, a simple / cheap fix in the end, so thanks again @Cee Jay

In response to previous queries, I thought the following images might be useful.

All the best,

Richard

https://cimg7.ibsrv.net/gimg/www.jag...44e41a2696.jpg
Inner boot, showing pencil length 'Suppressor' assembly in place before extraction and fix.


https://cimg4.ibsrv.net/gimg/www.jag...b7e2a15536.jpg
1N4002 diode in place (excuse the soldering!)

mine stopped working in 2014. I refused to pay $250 plus labor to replace. Thanks to covid, I finally got around to pry the assembly apart and have ordered a $10 LED strip on Amazon to fit inside.
https://cimg9.ibsrv.net/gimg/www.jag...9f1e3eb125.jpg
yes...time to fix this bad boy. Replacement strip will be here in 5 days
https://cimg8.ibsrv.net/gimg/www.jag...2a4babd934.jpg
opened. Use Acetone to melt the glue
https://cimg4.ibsrv.net/gimg/www.jag...74581a007b.jpg
https://cimg7.ibsrv.net/gimg/www.jag...74c696e6b3.jpg
Sealed LED assembly
https://cimg0.ibsrv.net/gimg/www.jag...70cbfdb7d0.jpg
screw
https://cimg1.ibsrv.net/gimg/www.jag...e3f23b953a.jpg
Pry tab open