I just bought a 99' E300TD, and I want to hook up a disc changer. The factory radio has a cd button and the original dealer window sticker says that the stereo is "CD ready." I have been told that there should be a hookup in the trunk, but I can't find this wire, unless its under the spare tire. I am assuming that the radio is an alpine because the seriel number is "AL2299W0930146." Does anyone know if there should be a wire in the trunk and where would it be. Any information would be greatly appreciated. Thanks.