is the transduser wire ran by any other types of wires at all it could be bleeding thru a power wire of some kind. Is it mounted on the out side of the boats transom? Make sure the wires are pluged in 100% and also look at the cable ends to make sure the pins are not bent over or pushed back so they can not make contacked with the head unit when pluged in. Make sure the tranduser is mounted as far way from the engine and also look behind the transduser on the bottom of the boat for any thru hull fittings, Or steped notches in the hull of the boats bottom that would line up with the transduser, If that happens you would get air bubbels around the transduser giving you fales readings. Is the transduser under water 100% at rest? Some times you can here and feel the transduser pulsing when it is really wet, When I say here you will need to put you ear to it really wet. If all that is ok or you can not feel or here it then you may need a new transduser first they do go bad
And if the new transduser dose not do it then some times the head unit will be bad also, But most of the time it's the transduser.
