The easiest way to hook them up so you will not have electrical interaction
problems is to attach the negative wire of the fish finder to the same
battery terminal as the negative wire of the trolling motor. That way both
items use the same "ground" path.

Bill Grannis
service manager

PerZakly

Get in the habit of connecting the fish finder and everything else (lights,
etc.) that way. Someday there will be an internal connection of that "ground"
to the boat and other users. This way no problems will develop.

cheers

oz