BM54 - non functioning CD autochanger
 

I have just upgraded my Hi-line sat nav system with bmw units (Widescreen with CD, Mark 4, 16:9 tuner and BM54 radio unit).

Having done this on another car using the BM24 radio there was no problem and all worked fine.

However with the BM54 there is no sound from the CD changer. The unit changes CDs OK but no audio from them. The radio, sat nav and single built in CD work fine.

Does anyone know what the solution is please? Do I need a different CD changer as well?

Thanks.

I suspect you have the CD audio wires the wrong way around.
Are you aware that the pin numbering of the small connectors on the radios is different?
On the 10 pin connector [BM24] pin 1 is the LOWER left corner.
Like so:
6 7 8 9 10
1 2 3 4 5
On the 12 pin connector [BM54] pin 1 is the UPPER left corner.
1 2 3 4 5 6
7 8 9 10 11 12
CDC wiring:
-----------10p BM24-----12p BM54------10p CDC Rover
Left+--------1------------8-------------6 KB
Right+-------2------------9-------------1 YB
Left---------6------------2-------------7 BK
Right--------7------------2-------------2 BY

My two connectors are exactly the same on the BM54, I don't have a 12pin and a 10pin?! I swapped them around till they worked, thankfully didn't do any damage on my investigations but there are several ways I could have put them in.

Thanks for that info Hans. I have an adaptor lead that apparently worked fine in the previous Rover 75 it came from. I have tried every alternative way of inserting the 2 small plugs (and now know how to flatten the battery in quick time!) but am totally clueless when it comes to interpreting what all the colour coded wires mean.

Having discovered how unreliable the BM24 units are, I am beginning to think that this BM54 also has a fault.

I have found the BM24 Units to be incredibly reliable and had none in for Repair.

Re the BM24 - I have had 2 units that would stop all audio output (including the sat nav) and/or become totally unresponsive to the volume control. In addition, the one I have removed flattens the battery if I refit it.

Are you able to repair these units by any chance, as it seems a waste to simply bin it. Obviously I would not want to sell it on to some other unsuspecting user.

Any help appreciated as I have not found a source for such repairs.

Ditto this. I can't afford a £200 outlay for a BM24. I have previously been quoted £42 but this was a misunderstanding and was actually the radio itself - probably the Harmony unit!

Love to know how to repair them... could make a small fortune.

Okay, let's try again.

On the BM54 you have 2x 12 pin connectors for the audio input.
The CDC uses the left hand side bottom connector [White].
The CDC wires go to pins 2 [common ground], 8 CDC Left+ and 9 CDC Right+.
The pin numbering as in my post above.
On a BMW adapter cable the colors are pin 2 Brown, pin 8 Yellow and pin 9 Black.
Can you trace the wiring from your CDC to the wiring harness?

I doubt your radio is faulty given the fact that audio output is OK.
Any chance of testing it in a nearby members car?

Hans

Hi Hans,

I have a Hi-Line setup in my car and my CDC has 7 connections not 4 - are we talking about the same setup?

That's correct.
Four wires are audio, three wires are +12V, Ground and Ibus.

Hans