I have a 1987 Stott Craft bass boat. Attached close to my trolling battery, in line with positive lead from battery to trolling motor, is a small part less than two inches long with in and out screw posts. Is this part a circuit breaker of some sort? It is sealed and I can't see what's inside. When I try to operate my trolling motor, I hear a click from the part and the trolling motor want turn. Thanks