Mercury - Temperature Sensor SC1000 Speedometer & VesselView Interface 56-820386A76. Overview. Some SmartCraft setups rely on a dedicated temp sensor to give accurate water-temperature readings on SC1000 speedometers and VesselView displays. The Mercury 56-820386A76 Temperature Sensor is the piece that makes those readings possible. It gives the helm a steady, real-time temperature signal so the system can display correct values on Axius, select outboard setups, and SC1000-equipped boats. Simple