i dont trust aux inputs at all. i tried to hook up my ipod using an rca-to-2.5mm connector, and the sound was horrible. i could only use the ipod wheel to adjust the volume, and my amp was on but there was no bass at all. i took it out about a minute after i installed it. as far as advice goes, i would check to make sure all connections are in the proper order, and also that the polarity of the aux cable is right. i dont have any experience with panasonic, but there might be some kind of setting to enable the aux input. also, there might be interference from another electronic source. where do you have the sirius receiver grounded? what are you using for your power source for it? thats where id start. dont know if any will help you, but its worth a shot. electronic gremlins are the hardest to chase down, but electronics are still fun.