I was getting ready to install the bilge pump in my 1988 bayliner center console when I noticed a round piece of equipment mounted to the bottom of the boat, sealed with epoxy and one green wire coming from it, but not hooked up to anything. I have scanned the wiring diagram for this boat to no avail. I looked under the boat and there is nothing protruding or any indication of something being installed in that area. Anyone have any idea what this mystery item is? Thanks