Unit snaps onto a base but no connection there. Power from battery and transducer cable plugs tightly into back of the unit. Everything is tight and the unit is relatively new, only about 4 months old, so no corrosion. Battery is a small fence battery, connections are good. Only thing I can think is transducer cable is cinched tightly to trolling motor shaft, though I doubt that is the problem. Only other suspect is heavy dew covered and then driving with it wet could have forced moisture into connecting port at the power cable. I’ve never had it that wet then driven with it. Also got it soaked in a downpour the last time I used it on the kayak. I know they aren’t water”proof” but assumed they are water”tight” to getting wet.
Otherwise, no clue.