Rear 3rd brake light not working.
 

I have a 2016 Jaguar F Type S AWD Convertible. The third brake light under the spoiler does not work. I have removed the light, and it works perfectly testing with a 12 Volt supply. There is no voltage getting to the light and am looking for some help in resolving this. I have downloaded the manual and can see that the power comes from the Central Junction Box. If someone could direct me to where this box is located, I would like to check the output from it and also trace the cables to see if I can find the problem. Any help or suggestions would be greatly appreciated.

Welcome to the forums Stubbsy,

I've moved your question from New Member Area - Intro a MUST forum for advice from members with the same model.

Graham

Stubbsy,

I had the same symptoms on my 2014 F-type V8S convertible. Here is the verbatim diagnosis that I got from an Indy mechanic. It should give you some things to test out for yours.

"Scanned vehicle and found code b1115-14 high mounted stop lamp malfunction. Removed brake light to check for power. The brake light is not getting a signal when pedal is depressed. Brake light works on a signal from the body processing module located in the cjb to supply power and has a fixed ground. Checked the ground wire- tested good. Removed carped trim on the passenger side floor to access connector c3bp01a pin 8 going to the central junction box. Tested wire from connector to the 3rd brake light- tested good. Both wires going to the brake light tested good and no signal is being sent to the brake light. The cause looks to be the body processing module which is internal to the Central junction box. Central junction box must be programmed by a dealer scan tool."

The Central Junction Box (CJB) is located under the carpet of the passenger footwell. Pull up the floor mat and you’ll see a rectangular cover that pops off.

Thank You
 

Thank You. I Have also received a reply as to where the CJB is and will check as described.

Thank You

Hi. I looked under the passenger footwell and there is no cover or anything that looks like it could be the CJB. Also looked under the driver's side and could not see anything however this is difficult due to the foot pedals interfering with the carpet..

Do you think it is possible that they moved this in later models?

Couldn't find it in either the passenger side or the drivers side, could they have moved it in later models?

Nope. Here’s a picture that shows the location. This is actually for a RHD vehicle (steering wheel on the right), but it’s the same location in the passenger footwell for LHD, on the front floor under the glovebox. The carpeted panel pops off.


https://cimg8.ibsrv.net/gimg/www.jag...3d5844e21.jpeg

Thank you but I am confused. I found the fuse box as shown in your picture but that is not the Central Junction Box (CJB) according to the picture I have and the description in the manual. According to the information I have the CJB does not have any fuses.

https://cimg2.ibsrv.net/gimg/www.jag...b86fa43199.png
https://cimg4.ibsrv.net/gimg/www.jag...1442e58e91.png

I am no expert, but check the Right Lower Side of your dash for CJB.
https://cimg1.ibsrv.net/gimg/www.jag...783a7e0378.jpg

The CJB does indeed have fuses and relays, and big connectors. Mine’s in storage so I can’t look at it right now.

With the lack of snow and warmer temps, hopefully yours is coming out of hibernation soon. I might bring mine out this weekend. :icon_banana:

Wow, would have thought the 3rd brake light got power from the same source as the brake lights.

Different signal line from the CJB. I’d check the ground, if you can find it.


https://cimg2.ibsrv.net/gimg/www.jag...d582290a0d.png

Redundancy, so they don't all fail together?

Rear 3rd brake light not working.
 

I have found that there is no power going to the 3rd rear brake light. With previous help I have now located the Central Junction Box (CJB) and now need to access the connector C3BP01AR which is underneath the junction box. How do you access this as it is underneath the large connector C3BP01CR. I need to do this to access pin #1 to test for voltage output and continuity of the wire to C34l

Stubbsy,
Check to see if there are any software updates before removing hardware.
I would reprogram the module responsible for controlling the taillight with the latest version possible.
If no update is available, I would attempt to reprogram with the current software.

best regards,
Bill