I was riding today and stopped at a water hole. When we got back on the bike my passenger's intercom was not working. She could hear the music, and she could hear me but when she tried to speak I could not hear her and she did mute the music. I checked the connections both at the helmet and at her plug and the helmet setup is only a month old and then only used three times.
Any Ideas ??????

 

Try swapping the cords between the 2 headsets. If the problem moves to the rider, then the cord is bad. The cords can be purchased separately. Last time I had to buy one was a long time ago, but it was only about $20. Good luck.