Through process of elimination. Break each circuit by pulling the fuse and/or relay.
Do you have a hidden antenna in the fairing?

 

As far as the system goes, completely stock. I have a Harman Karmon C.D./C.B./Intercom. Stock antenna's, nothing has been added or changed.

 

Hey, Max. Just so you know, using an email address is great as a username. It's easy to remember. However, when you include your first and last name, it makes it easy for people to find out interesting things about you, especially when they know the city and state in which you live. Maybe you're not concerned about that kind of thing, but I just thought I'd give you a heads up in case you are concerned about that kind of thing.