I have a 2011 FLHTK with the factory intercom system. I put Love Jugs cooling fans on my bike and they are powered thru the factory ACC. connector under the seat. I am getting "noise" in the headset when plugged in the front"driver" location but no interference in the passenger headset. I have factory boom audio headsetsand have tested both in both positions. Only the front connection is exhibiting interference. This all goes away when the assessory switch is turn off killing power to the fans. My bike is all stock with no none harley accessories and the fans are the only thing connected to the accessory system

 

How are you grounded?

 

 

I would suggest to try that first. If you can run it to the negative post of the battery or a grounding post by the battery. I would think that would alleviate the buzz.