I am hoping someone can give me some help on an electrical problem. My engine has no power. The power trim switch on the engine and on the boat has no response. There is no electricity when I turn the ignition switch either. There are no lights on the panel and the engine will not start. There is absolutely no sound. I have checked all the fuses and they are good. There is 13.4V of electricity going into the motor. Howerver, I did test the voltage on the other side of this round thing that the main power from the battery is connected to and it has no voltage at all. I am wondering what that black round thing is and if it is the causes of my troubles. Any help is much appreciated.