My 2007 LTD came with a very nice Sony touch screen radio that mirrors my Android phone but when I connect to Weblink and tap the rear camera icon, I get the message "no signal found". I'm guessing that when the Sony was installed, they didn't add the rear camera device. I've been getting different stories from installers in my area so I thought that I'd turn to the forum and see what you folks think. One, if I purchase a license plate camera, does it have to be hard wired to the radio to get the signal? And secondly, since the radio is bluetooth abled, will it just hook up wirelessly to a blue tooth camera without a hard wire? Thanks for any advice!