Just FYI, there is another way to add an Aux-in that requires some minor soldering to the main board. This is done with 4 small wires with capacitors (2.2uf polarized) connecting to 2 seperate areas on the board that coincide with the onboard chip. While your install does seem much more simple, I'm curious as to how it sounds. My only concern is that the source wouldn't come through in true stereo. I say this because the phone input is only mono but you seemed to have tapped into the actual H/U itself.
I've attached some rough diagrams detailing how the internal mod is done. Note that it requires an 1/8" switched jack that you can buy at Radio Shack. 5 wires will come from the jack (2 positive, 2 negative, and 1 ground) and 4 of them will terminate with a 2.2uf capacitor (2 will be positive, 2 negative). The other end of the capacitor will be soldered into the points specified and the ground will be attached to the H/U chassis. Once this is done, there are no CD's required in order to play your MP3, IPod, SatRadio, etc. When nothing is plugged into the jack, you have an open circuit just as normal. Once you plug into the jack, it closes the circuit and switches to your Aux. unit. The sound quality is very good and, because it is going directly into the board, has almost no signal loss.
exwrx: I've also attached the datasheet for the processor. You are correct that sharing can and is done on the board. Also the second diagram shows the use of a 5-pin (or 4-pin + seperate ground since I can't seem to find a 5-pin) connector which will allow for quick disconnect if you want or have to take out the H/U. As an added note, the 3rd diagram shows in picture form just where the wires go. It also shows that the caps that were removed from those points are being used again. Most have found that new caps are better than the ones that were removed though so keep that in mind.
If you or anyone else is interested or has any questions, feel free to let me know. I didn't come up with this mod and all credit goes to those who were brave enough (and smart enough) to fiddle around with the insides until they got it to work.
