ok i don't have a JVC HU, but i think this is pretty much the same for all HU. so yea...i have a pioneer HU and there's no real aux cable for a mp3 player, so wut u gonna do it go to your local electronic or audio store. ask them if they carry a aux cable for JVC that has a rca input (female). Then you just go to radio shack or somewhere and buy an adapter that connects to your mp3 player that has a rca output (male). Connect the two RCA's and now u can play your mp3 player on ur HU.