I ordered an AUX cable for my CLK W209, but when I tried to install the cable I noticed that this is the wrong one.
The car has COMAND 2.0 and I'm not sure about if it is retrofited.
This is the cable I got - http://www.metasolutions.co.uk/merc/210_440_50_05.jpg
And this is the only free slot in the COMAND - ImageShack® - Online Photo and Video Hosting
I saw that there is some kind of a plug, that converts these large pings to smaller ones (the cable doesn't fit because pins are 2 times bigger and the plastic doesn't go inside).
I have this COMAND - a 203 820 96 89 80
P.S. I'm not sure if this console does support AUX, I found that I can switch to AUX from system settings, but not sure if it is what I think.
Think I found something.
In the 2 picture you can see that few wires are simply cut off and added with a tape.
I checked google for what is that connector and found it is CONNECTOR C2, connects a lot of things, including AUX.
It could be possible that those cut off cables are for AUX and some other things.
Couldn't find color wiring for COMAND 2.0 yet, only know that the pins are 4,5,13,14.
I could simply strip the wires and add them to AUX plug, but I don't know if those are the correct cables.
I successfully added the AUX cable, I stripped the cables from COMAND with the same colors (silver=white) and soldered them together.
It seems that some cars from factory are made without the AUX support, so they left the port undone.
Maybe someone will find this useful.