The panel board indicating the levels of my black, grey and water tanks always shows E.  I have cleaned the sensors in the black tank as recommended in tech bulletins, to no avail.  Do I need new panel and where can I get same?

TANK INDICATORS- Fresh water tank, Put a quarter cup of baking soda in solution in your water tank,fill tank approx 1/2 full with fresh water.See if you get a reading.If not apply 12 volts to wires ,[Use Battery charger on 2 amp setting].If that does not produce a reading you have a bad connection or defective probe.Gray and black tanks.- Use same 12 volt method ,fill the tanks with water ,you should get a red light indicating full tanks.The readings on the gray and black water show only only full, not how much. Good luck Bob Chaney #2626

clipperskipper, since you are reporting that all of your tanks are having level problems, I would suggest that you check the common wire from each tank to the display unit (they may all be connected together before the display unit.)  The common wire will be the lowest wire/probe on each tank. I would check the wiring bundle from the display unit to the floor first - for a broken wire.  Hope this helps.
Ed