My subwoofers arnt playing sound. My amp is working as tested in my brother's car.and so are my subwoofers as tested.my cable connections are correct as amp turns on and I plugged in another amp that turns on aswell but still won't make subwoofers play.i replaced my remote cable and rca cables with new ones and still won't work. My door speakers connected to my digital star sound radio head work perfectly. I noticed that when I drive over a bump my subwoofers connect and disconnect or they connect and play for a short time and I start to hear them disconnect and connect like a loose connection until they turn off again but amp remains on. Some one please help.