Car audio help please
 

Hi there, I would like to connect an MP3 player to my car CD/tuner, no biggy I thought.
The standard head unit is a Blaupunkt single disc player with tuner and provision for a CD changer. I have the Blaupunkt auxilary input lead which has the blue plug on one end which goes to the changer input on the back of the head unit and a 3.5mm jack on the other to connect to a MP3 device. However when this is connected the head unit is not seeing a device/ changer; hence no music out. On the pin out connections of the changer socket there are additional pins which are not connected to the lead; Vb ( which is 12v ), Data in and Data out. ( The lead is connected to AF-L, AF-R and AF-Ground )
Does the head unit require a data signal from a changer before the head unit recognises it ? and if so can this be tricked in any way ?.
Any help or sugestions would be appreciated.

I do know that the retailer "Motorworld" can supply a kit for this intended job, but at £110 I was hoping to achieve the same for somewhat less. I can have a new tyre for that.

Thanks

I've just finished wiring in a CD player to mine (saving £30 by making up my own lead) so got all the Blaupunkct connector schematics off the net. Have you actually tried pressing the CD changer input select button (top rhs on my radio) with the MP3 player running? If that doesn't work then as you obviously suspect the radio may need a signal to tell it something is connected.

I presume you are referring to the C3 connector (rhs of the 3 looking at the back of the radio)? If so you should have the following (from the top)

Row 1 = 13, 16, 19
Row 2 = 15, 18
Row 3 = 14, 17, 20

13= Bus in
14= Bus out
17= Bus Ground
15= +12V perm
16= Switched +12V
18= AF-Ground
19= Line in Left
20 = Line in Right

I assume your connector is wired to 18, 19, 20? Maybe you need to loop +12V (ie pin 15) to pin 13 (ie Bus in) so the player knows something is connected? That would obviously be risky though if its expecting a 5V digital signal :-( Might be best then to check the volts on "bus out" from the radio that should give a clue. If its 5V then you could try looping "Bus in" and "Bus out"?

This input to the radio is definately used by some hands-free sets so you could try searching for info on those as it might help. Other than that you could try searching the rover MG forum as they mostly have Balupunkt radios fitted and they have a specific audio section for posts.

Good luck,

Keith

can you put a y-cable 3.5 splitter in there ? 1 to mp3 1 to CD changer ??

Thanks Guys, Keith, I did try looping the 12volts. but this had no effect. On this unit the phone connections are on another plug. Also a Y splitter would not help as I do not have a changer connected.
Bit more research required I think.