Originally Posted by brucebollert
I have a 2016 FR sunseeker MBS. Does anyone know how the gray water sensers work? Are they inside the tank or outside? Can they be replaced? Mine havenít worked since 1st year.
The sensors are essentially just machine screws with the heads inside the tank and nuts outside that compress a rubber grommet as well as provide a means to connect wires.
Nothing mechanical or electronic, just a conductor. When liquid completes the circuit from the lowest conductor (the common) to the next one up it triggers the first level indicator. Repeats for each one up the side of the tank.
Because these "conductors" are close to the tank wall it's easy for any crud that builds up on the tank wall to short from conductor to conductor and create false readings.
They can be replaced but if you are doing so I'd recommend replacing with the Valterra "Horst Miracle Probes" which have a different design. The probe extends the contact point significantly away from the tank wall and short circuiting is avoided.
Same type of probes for the black tank are made but also include a half round tube that shields the top of the probe from any solids from fouling and shorting the probe itself.
Available on Amazon.