I'm not getting any sound out of my four speakers that are connected to the stock amplifier. I bought a wiring harness from Best Buy and there's a blue/white one for amp turn on. I also connected this one to the one from the deck and have no sound from any of the speakers. I thought it was my other deck causing this problem, but just bought a brand new deck. Before sound would cut in and out, so I thought a wire might be loose or maybe my stock amp is shot?