I just installed an aux input in my nav equiped 06 MCS. It was not a simple as reaching behind the radio and plugging it in as I had been led to to believe. The place on the radio that the aux plug goes into was already in use by a socket with two wires. I solved the problem buy pulling the head unit and removing the two wires from the original socket and transfering them to the aux input socket. I plugged the modified aux socket into the radio and tested both the radio and nav system and all worked well. The only thing is that what I had thought would be an easy half hour job turned into a couple of hours so be forewarned.

 

So I just bought a 2006 MCS and it has nav and the HK stereo. I just installed a aux input which was taken from a 2008 model it has three wires a yellow black and clear. I saw a post on which pins to connect them to and to move my nav voice to the same connection and it worked... PROBLEM... I am only getting the vocals from the passenger side. Mid range and bass are working but not vocal. It works perfect with a cd mp3 and the radio but not with the aux.... Any suggestions?

 

Your use of the word "vocal" is very confusing. Can you describe it a different way?

 

The music plays clear from both sides but the main voice is not playing on the driver side, only the passenger side. I do hear all the background music and the back up singers but not the lead. My aux cable only has 3 wires and all the others I have seen have more. Could this be a problem with the HK speakers and the cable. I have a yellow black and clear wire and they are put on pins 3 4 and 10.

 

What you describe, and for it to happen only through the aux input, is technically bizarre. Does every recording have the problem? What does instrumental music sound like, or spoken speech (e.g. podcast or audiobook)? The best test is to take one of the recordings you have a problem with, and create a monaural (not stereo) recording from it. Play the mono recording through the aux input and compare the output from the left and right channels.

 

I have isolated and tested and done everything I need to know the breakdown of the pins on the radio and the breakdown of the wire harness . yellow black and clear wires

 

Pin 3 black wire is aux input L+.
Pin 4 yellow wire is aux input R+.
Pin 10 is aux input -.

Swap the yellow and black and see if your problem moves to the other side (you should hope that it does because it would mean that the issue is in the aux cable; otherwise it is inside the head unit).