Hi all,

I hope nobody minds that I've posted this on the 7 series forum as well.

Need a little help please.

I have a RHD 1995 740i with DSP, Bluetooth hands free & Sat Nav and am trying to install an Xtrons Head Unit.

I've modified the head unit to make it fit and run the 5m extention cable to the trunk.

Attachment 637699

This is the pin out for the Xtrons.

Attachment 637700

This is the pin out for the stock radio.

As you can see from the bottom of the diagram, I've mapped out the corresponding pins from the 17 pin extention to the 17 pin radio plug and they all seem to line up with the exception of the rear speakers. I assumed it would just be plug and play, but no such luck.

Then I tried the radio in the trunk trick.

Attachment 637701

Still no sound.

I tried connecting ANT (10 on Socket E) to the blue/white AUTO ANT (16 on the radio plug), no sound.

I've connected a speaker to the +/- speaker outputs on the extention cable to make sure the Xtrons is sending a signal and the music plays fine.

I've tried disconnecting and reconnecting the various modules in the trunk (CD Changer etc) to no avail (getting desperate by this point).

Messed around for so long I flattened the battery. I've read every post on every forum I can find but still no sound.