[niles]

DV:

I didn't read where you changed out the "sender or transducer" -My vote.

Related tech story: back in another life on nuclear subs; all gauges and indicators were triple or quadruple redundant. Sounds and is expensive; but absolutely neccessary. one guage off scale- bad- but tells you nothing. Two gauges- one says A the other B. You still know nothing, other that one of them is wrong. Third gauge(source) indentifies which one is the likely providing faulty readings.
Forth guage confirms with high probablility the real answer. I had this exact scenario play out one night at test depth when the main depth gauge at the con indicated that we exceeded test depth and were about to implode. Thankfully the gauge went T.U. for no reason with no warning.

gn