this is wierd! black tank senor problem

We have the same problem with our Techma toilet in our MH. The Techma uses ultrasonic sensors which are glued to the side of the tank. It can have one or two sensors depending on how it was installed. The LED will will go yellow then red. It's common for the LED to go red well before the tank is actually full. Exactly why I don't know but it does. I removed my Techma sensors, cleaned (by grinding it flat) the tank side and re-glued them, and it didn't help. Now I will un-plug the two Techma sensors and just go with the regular pin sensors. Not sure how the Techma's computer will react when I do this however. MH is in Winter storage right now so it'll be a while before I can try it.