I just bought a new Sony head unit for the '03. There's a note in the installation guide that vehicles with antennas in the window may have a booster, the new harness has a wire to plug into said booster. Do i have a booster? I didn't notice anything when i took the factory unit out (2-harnesses and antenna connection). I don't want to get lousy reception from a new radio. All the other wires are accounted for. Thanks