When I purchased a used 1995 23' Sea Ray 5 years ago, it already had installed a Humminbird Wide Vision depth/fish finder. Also installed is a Lowrance<br />3500 Digital Depth Sounder. I don't know how the Lowrance gets its sonar signal, but there is no (sonar)switch. Initially, the H'bird would show fish but in the last few months has rarely shown such a display.. Bottom is shown, no fish. I have tried isolating all of the wiring (FM radio,VHF, Lowrance) under the dash from each other to no avail. Is there something I can do? Is the transducer going bad? There is some kind of disc (aprox. 1.5 inch circular) mounted in the bottom of the hull off the port/stearn side. Any guesses on whether its H'bird tranducer, temp sensor or Lowrance? It has had bottom paint applied which I have scraped off. Also I can see, but not reach, what I think is a thru hull tranducer - looks like a computer mouse on steroids - attached to the inside of the hull forward and portside of the engine. <br />Only thing left to say is salt water in winter and fresh water in summer. Suggestions?
