Upgrade to a Symphony Radio, with CD Autochanger

[BRG75]

Changing a Harmony radio (BMW / MGR connectors) for a Symphony (ISO connectors), with and without the CD auto changer.

First of all, for around £6, adapters are available (if the auto changer is not required)
The Symphony radio will function, but the steering wheel controls won’t.
However, purchase two adapters for £12, transfer two wires and they should work.
Transfer a third wire, and the Symphony’s K bus automatic volume variance should also work.
Alternatively, for £20 +, you can buy an adapter which will give steering wheel controls. (but I don’t know about the K-Bus)

As far as I can ascertain however, none of the above will connect to the CD changer.

For this you need a “No Longer Available” sub loom, or a visit to the breakers.

Much information exists on this forum, going back for 10 or 12 years, but a clear picture hasn’t really emerged.

I would appreciate it if somebody who has experience of this change might vet the details below, and make corrections / additions as required please.

The standard car loom uses the BMW style round pin connector, which plugs directly into the Harmony Unit, and includes 2 wires for the steering wheel control switches.
I believe it also plugs directly into the High Line unit (but I don’t know about the Low Line)

It does NOT connect to the Symphony Unit, for which there appears to be factory fit additional wiring, together with non factory fit (but factory supplied) alternative additional wiring.
OR
After market adapters, as above

I have come across the term overlay looms, which I assume means supplementary looms.

So the first of these, (which I’ve included, although I don’t think that it’s Symphony related) is part Number VUL 100310

* Factory fit, and adds the Alpine CD changer to a Harmony Radio.

It appears that a number of (specific) extra looms existed, numbers not known, to

a) install a Symphony radio
b) install a Symphony radio and CD changer
c) install either Navigation options, with or without a CD changer.
d) connect the Telephone Kit
Plus different permutations, of the above.

I have read that the above variety of looms were manufactured, so as to eliminate surplus plugs and sockets, on production cars.

On Post Production upgrades however, the reverse was the case, and it was simpler to have a catch all loom, which was manufactured by Lucas, for Rover / MGR. VUL 100330

* Dealer / Owner fit, and converted BMW to ISO, plus catered for all permutations of options available. This cable is “No Longer Available”

Looking now at the CD changer, whilst they appear to all be model number CHM S620, there are 5 different part / type numbers that I have found listed.

Of significance, is a black interface box, that is plugged into the auto changer with an 8 pin round DIN connector. However, it is plugged back into the various radios and / or their wiring looms with what appears to be radio specific connector styles.

I don’t know if these different plugs are the sole difference, but I have found the following interface part numbers :-

R75 – ALP (Harmony to CHM S620)
R75S – ALP (Symphony, with bus lead in glove box, to CHM S611 / 620)
R75Si – ALP (Symphony, without pre-wiring, to CHM S620

I will update this, when I have identified the loom that I require, or just the connectors, as I have most, if not all, of the pin outs that are required.

Regards

Mike

[raykay]

One of the problems is that the BMW connector has 17 pins, the two ISO connectors have 8 each = 16. The missing one is the K-Bus.
In the MGR BMW to ISO lead (VUL100300), there is a sealed joint in the K-Bus cable, one to pin 19 of the blue mini ISO connector for the Symphony, the other to the connector for the CD unit.

[BRG75]

Thank you for that.

I have a photo of VUL 100300, but of course that sort of detail can't be seen.

All good fun though.

Regards

Mike

[The Rovering Member]

I'm hoping to make the conversion quite soon so am following with interest. I have a variety of leads, probably all wrong if a square of grass has anything to do with it..

This site has by far the most ridiculous word editor l have come across.

[BRG75]

This went into the background for a while, but has not been forgotten.

Will be posting wire loom info. in a week or two.

Meanwhile, I have bought a boot mounting bracket, on e-bay, which has posed a minor question.

Can anyone who has a boot mount Alpine CD changer tell me if the right hand boot faux carpet trim is simply cut at the top, for the changer to protrude, or was there a specially molded piece.

Many Thanks

Mike