I have a 99 grand prix se with the bose audio system. I recently hooked up a new radio. Everyhing works except the sound. There's one input that plugs into the factory radio,that i can't plug into the harness kit,and the harness kit is the correct one. It's a red wire with a black and red input on it.I think its the plug that controls the sound and i can't figure out where it goes. Do i have to splice it or what??? Help!!!!