Ok so I have a 2002 mustang v6 premium and I installed a new kenwood radio. Problem is there's no bass now. There's no amp in the trunk so I'm sure it isn't a Mach 1000 but the speakers on the inside of the doors by the mirror say Mach so I'm assuming it's a 460. I went to Best Buy and the guy there gave me the wiring harness that was supposed to be for my car but now there's no bass. I have no idea what to do. The wiring harness he gave me had an extra wire. The rca plugs fit in the back of the kenwood but the plug that's supposed to connect it to my car doesn't fit the wire coming from behind my dash. They both look like they should fit but they just won't lock together. Should I get a wiring harness for a base model instead of a Mach 460?