The Aux adapter plugs into the factory radio's CD changer input. When you press the CD button twice on the factory radio it activates the CD Changer mode. You use the RCA out on the aftermarket radio to connect to the Aux box.
I tapped into the power wire of the factory harness. The harness that comes with the install kit helped me find the wire to tap into. I plugged it into the factory harness and traced the wires.
If you want to use the aftermarket radio for all functions, hook up the factory antenna too. The factory radio will still be a CD changer when when you need it to be.
The only thing is, when I bought that Aux box it was 45 now the price is doubled. If you don't want the factory CD changer to function, you can forget the Aux box and use the harness that comes with the dash kit. Your climate control will still work but the factory radio will be a good CD holder. It actually does work but no sound.
Oh if you have a double din after market radio, use the Honda audio attachment kit.
