I have an '04 Duramax, and was just wondering how to make the radio stay on for more than the five minutes it does stock after the key is turned off. Sometimes I like to turn up the tunes while I work on my truck, but don't want to have to keep on turning the key on and off through thr open window for five minute sessions. Also can I get rid of the radio shutting off when the door is open, and the annoying door chime too?? Thanks for your help guys- ;)

You could leave the key on the first notch or you could wire a switch to keep the radio on.

Would a switch work on an '04? I thought it used serial data to turn the radio on/off from one of the body control modules.

Yes you could still use a switch to simulate the ignition being on. You should only need to power up the brown ignition wire.