Yeah. Sorry about the bogus info. I guess that they just have a switch inside the unit activated by that grey wire that just switches whether the audio source is coming from the CD changer or the aux inputs. Oh, well. (Edit: Nope. It actually claims that, when switched back, the changer will start playing where it left off, so it has to also be sending some sort of signal, like a pause and de-pause or something, to the changer as well. Obviously, I don't know what I'm talking about.)

Hmmm. On the instructions for the Alpine/Audiovox controller, it explicitly states that a changer must be attached, but it doesn't say that on the Kenwood one. I'll bet it does require a changer for both, but it's probably worth calling them to find out.

On the other hand, they obviously know enough about the signals to be able to translate from one system to the native GM system. You'd think they could figure out a way to fake out the GM system to allow aux inputs. Who knows?