Optic ... plug under seat?

[gotaflat]

Ok .

So I am doing few minor things to the d4 and while trying to figure out if the Bluetooth module is toast (yeas it’s stopped) I found this cable under the drivers seat ??

I have RSE and that works fine .. so what am I looking at ?

Assume it’s nothing to do to with the Bluetooth module? https://uploads.tapatalk-cdn.com/20200628/a1c7acd2f221ca1bc12e1adeff79f0c9.jpg

[Cambo_oldjaguar]

That's the SPDIF connection from the 6-stacker DVD player, the audio from the DVD player runs directly to the amp, not via the head unit.

It's nothing to do with the bluetooth.

[gotaflat]

So... it’s meant to be plugged in? I have the 6stacker in back ...

[Cambo_oldjaguar]

Only if you have the Logic7 amplifier, and from your pic you only have the regular Harman Kardon, not Logic7