Installing new audio system in 2003 dodge truck looking for wiring info on factory radio.

Whenever I am planning to work on an unfamiliar vehicle or system, I go to the library and access the Mitchell's Manuals in the reference section. They cover domestic and import trucks and autos. They have separate manuals that cover electric systems and even component locator guides, as well as A/C, emissions, transmissions, etc etc. I spend 10 cents per page to copy the needed pages so that I don't have to trust my memory. While not as comprehensive as a factory shop manual, Mitchell's is much more detailed than Chilton's or Hayne's books.

Some after market stereo companies sell wiring harnesses that will plug after market components directly into your existing system.

Hope this helps-good luck