A:Answer They installed an auxilliary port with an ON/OFF rocker switch in my car and tied it into the radio. To play my mp3 player in my car, I plug it into the aux port, set the FM selector to the correct channel, turn ON the switch and enjoy my music. The port and switch are very small things and tucked away on the underside of the dash - pretty well hidded but very easy to access. In the picture, you can see how it looks. I'm very happy with this installation.