when i replaced my head unit best buy told me to buy a certian adaptor for my radio. Turns i didnt need it beacuse there was an adaptor already on that fit the stock head unit. Its hard to explain what i am trying to say but just take the antena whire and just pull on it to get some slack and see if there is a part you can pull off that will fit your aftermarket radio. if not go to best buy or a car audio place and they will give you the adaptor you need.