Just an FYI and something to look for if you have problems with accurate readings.
Last October I took the boat into the dealer for the ten year service as I didn't feel comfortable doing it myself. While it was in there I had them look at the heater and horn since both had stopped working.
My gauges have always worked but the alternator output drops as you rev the engine. Dropping as low as 10.5 to 11 at 4,000 plus rpm. I knew the alternator was good and so never addressed the quirky gauge reading.
Under the dash the dealer found one ground wire that had a bunch of other ground wires spliced into it. The dealer separated and ground each individually. Finally got the boat in the water this weekend and the alt. gauge reads steady between 13.5 and 12.5 even at 6,000 rpm. Heater and horn are now working also plus all the off/on buttons for the accessories finally work correctly.
