O.K., I am no expert on Ford factory radios, but I have spent considerable time recently on my CD-6 radio in a 2001 Excursion. The CD-6 radios have many inputs and you could likely cluge together a solution, but I will share with you the direction I took, as it is clean and leaves additional options available.

First, several companies offer a device called an Auxillary Input Converter which will plug directly into your head unit. These come in several flavors, depending if you want to retain any present devices that input into the factory radio (additional factory CD changer or DVD player in 2003), and/or if you wish to be able to connect more than 1 additional source into the unit (ipod, DVD, etc.) These will only work with head units that have a CD button. I do not know about non-CD-6 units, but all CD-6 units have this feature/button.

With that said, a supplier for at least four different brands of Converters is Logjam Electronics. The url for the listing of those that can be used in our vehicle is http://www.logjamelectronics.com/auxford.html.

If you were to go to the manufaturer's site for the various brands, you will find extensive documentation for some of the products. However, to save you some time I can tell you that installation is a breeze, and operation is even simpler. Once installed, simply press the CD button to toggle through the connected devices. For the PAC model, you do have to toggle an on-off switch to toggle between an existing DVD or external CD changer and the input(s) connected to the Auxillary Input Convertor. I do not have an external CD changer, so I can toggle between the existing internal CD changer and the external input (DVD layer) with pushes of the CD button.

Though simple, it took me awhile to discover this option for the installation of a 2003 factory DVD player into my 2001 Excursion without using an FM modulator (those things are pretty bad), so I thought I would share my story.

Good luck.