Aux Input for BMW 325i Business CD

Make your own AUX input cable to connect a mobile phone, MP3 player, Ipad, or any other audio source to your car's radio system. The process is very simple but requires soldering skills at some point. Removing out the radio from the car is a very simple process but not discussed here since there are 10's of video's on youtube showing this process. The pics are very clear showing exactly where to solder the wires and how to connect the 0.47 µF x 4 capacitors. all the process can be made in 1 hour time and costs less than $2.

You can also make hands free calls and hear the audio from your car's speakers with superb quality.

Note: The Iphone's original socket has 4 pins, the forth pin is for video wich is not needed in our case, here we used a clasic 3 pin stereo socket that plugs into most devices including Iphone with no problem. So just use a normal 3 pin stereo socket as in the pics.



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    6 Discussions


    1 year ago

    how to connect this?


    2 years ago

    Looks like you are directly inputting audio signal to TDA7376B chip - Power amplifier for car radio. Can you still use the volume control in the car when using aux input?

    2 replies

    Reply 2 years ago

    Once you plug the new aux into any sound source, you'll hear both the radio and the phone sounds both coming from the speakers at the same time, just lower the volume knob of your radio and the radio's sound will disappear keeping only the phone's sound. You can control volume level from the phone itself.


    Reply 2 years ago

    Thanks Nick. That clarified on what I was looking for. Though not required I will use a 'silence' CD in 'CD' mode and then will adjust my volume in the MP3 device.