[BRG75]

I believe that I can answer your question, as I have recently researched Harmony to Symphony, with CD Changer; resulting in some notes on wiring looms and connector types.

In a nutshell, yes you should be able to do it.

The Harmony, and the High Line Radio units both use the BMW / MGR single round pin connector. However, as you have stated, the Harmony is mounted in the centre console; whilst the High Line (radio unit) is mounted in the boot (saloon) or rear (Tourer)

Is there an extender loom, behind the head unit position, which goes to the back of the car?

If there is, unplug it; then connect a harmony unit in it’s place, and you should be working.

If there isn’t, you will have to cut the plug from the back of the car, and relocate it into the loom, behind the head unit. This would involve solder and heat shrink tubing.

Other than safely securing the other connectors that you will no longer be using, that should be it.

It would be prudent to plug the harmony into the boot / rear first, to check that it is working.

From my understanding, the steering wheel controls should be working. There may also be a K bus wire, but the Harmony doesn’t use this, so simply isolate it.

NB
The high line head unit is made by Alpine, but the radio module is actually Phillips, as is the Harmony.


Regards

Mike