Quote Originally Posted by NCSUmoombaMAX View Post
I'm a little confused... If the key is turned to the left to the "ACC" position, doesn't this accomplish the same thing? Why would the audio system need to be wired to it's own separate switch?
When you go from the RUN to ACC position and then from the ACC to the CRANK/RUN positions, there is an interruption in the switched 12V turn-on signal to the head unit. So it shuts off and back on. This can wreak havoc with blue tooth. Sometimes its a short pause in the music, sometimes, you have to re-pair the phone.

Replacing the ignition key switch with a manual rocker switch keeps the head unit turned on, regardless of the position of the key.