If that does not work I would try getting a new instrament module. That little black box that sits under the dash and your guages and pitot tubes are connected to it. This box was having problems in alot of boats. The guages would either read in the middle of the guage or they would not work at all. I believe Skiers choice has since swithed modules because I was lucky to get a replacement of that exact one. I was told they had "phased them out to a different manufacturer".