First let me say,I am aware that the HID headlamps make a high pitched noise right after shutting car off. Others have already discussed that here on forum. My concern is: if I am listening to radio in car with key in accessory position and I turn the auto function off so that lights shut down, should the ballast module continue to make that high pitched noise? Mine never shuts off (ballast module & high pitched noise) in the above scenario and I am wondering if that is why I have been unable to listen to radio without my battery dying. Just a thought as I attempt to troubleshoot battery issues. Any input appreciated and thanks in advance.