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Help needed with wiring

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  • Help needed with wiring

    I would really like to add an auxillary input to my cars standard tape player. I have seen various threads on the net where this has been done, but not on my exact headunit so I am struggling a little. My unit is a Philips PH7850 BMW Business RDS unit. I have opened up the unit and can see the ribbon that comes straight off the tape player head and goes down onto the main circuit board. This ribbon has 5 tracks on it. I need to know if this is the best place to wire in my auxillary connector for my mp3 player, or if it is better to try to find somewhere else on teh board after the amplifier circuit so that I will just be hearing the sound form the player and not an amplified sound. If the head connections is the best place however how do I go about finding out which of the 5 tracks are for Left, Right and ground which I believe are the only 3 connections I need to make. The head has 8 pins coming out the back of it, 4 of them on one side are all connected together and form 1 of the 5 tracks of the ribbon.

    Here is a picture of the ribbon coming off the head

    I can't seem to find a wiring diagram for the headunit otherwise it would be a lot easier.
    I have removed the tape player mechanism from the unit and found out what IC i have on the board, it is a TDA7313. I have found the datasheet for this IC which shows left and right inputs 1 2 and 3. Problem is, how do I find out which input is which, i.e which is FM radio, which is AM radio and which is cassette player? I need to find a wiring diagram for my radio I think in order to see what is going to these pins on the IC but I cannot find a wiring diagram for my unit which is a Philips PH7850, 22DC785/24F. Can anyone help me in identifying which input is which so I can ideally tap into or replace the AM input as I wont be using AM.

    Any help would really be appreciated