Hello,
I'm searching on the electrical diagram of the factory bluetooth installation on xk8 (typically 2005 model), precisely the wiring diagram of the harness LJJ3540NA or LJJ3540PA (native bluetooth installation).
The 2003 model year electrical guide describes only the factory fixed phone, not the factory bluetooth
I cannot find this information on the forums or on the web...
Does anybody can help me ?
Thank you

 

I never needed the telephone schematic for either of my XK8's and hadn't realised the BlueTooth one is not in the Electrical Guide.

However, I did need to identify the pinouts for the yellow 14-Way connector under the centre console and this may help answer some of your questions.




Graham

 

Having installed an after-market bluetooth system in my car, I can confirm that the yellow connector under the arm rest has most of what you need to direct a call through the factory radio. From memory, only the driver-side door speaker outputs voice calls.

A couple of observations: the switched 12V goes down with the ignition, so you cannot continue a call on the factory system with the key in and ignition off. Ideally, you need to find a switched 12V wired to the ignition key switch (turns off when the key is removed). The scenario is finishing a call in the car after you get home and want everything off. NPR listeners talk about driveway moments when they finish a story in the car, engine off and radio on. Being able to do that with a call is nice.

Also, some systems claim various levels of background noise processing abilities, obviously more important in a convertible than a coupe.

A bluetooth system will likely have full stereo out for music, and that needs a separate solution as the factory radio has no auxiliary input. There are several solutions, each with their own sound quality, technical complexity and required sequence of buttons:

• Work some sort of tap into the CD sound cable from the changer in the back. It needs to somehow be switched to preserve CD music
• "hack" the cassette deck heads and solder in sound input from the BT device. The cassette deck has to be "active" with a cassette pushed in for the sound to come through AFAIK. I assume the tape has to be removed.
• Install a _WIRED_ FM modulator and tune the radio to a preset radio station

There are also "external" solutions like trick cassettes with aux input, or even stand alone systems with an external speaker.

In my experience, you have to really think through how all of that works in some detail, including what sequence of buttons you are willing to go through to listen to your music, what happens when you get a call when on music mode, what device has control over what, etc. To me, the best devices are the dumbest, so you can control everything from the phone. Some device try and be too smart and control too much of the experience, leading to stupid competitions like control of music volume by the BT device, the phone and the factory amp.

In the end, when everything is setup right, you can listen to your music from your phone through the factory radio. When a call comes in, the phone pauses the music at the press of a button, you get a nice clean call with no background noise, and the music resumes when the caller hangs up.

The experience can also be much more frustrating with fiddling with controls and buttons to get the music going at the right volume and quality. When the call comes in, it is barely audible or super loud, requiring more fiddling with buttons. When the call ends, music resumes at the wrong volume again. After all, you can always put an incoming call on speaker for decent sound quality and no fiddling, and it's likely legal to do that in most jurisdiction as long as the phone gets nowhere near your ear.