I'd like to welcome to iboats :welcome: We enjoy new members...
Curious reading about your trolling motor. When you stated that last week it worked fine, was that just in the air or did you actually put the foot section in some bucket of water for the driveway test? Reason I ask is because is there anyway water filled up in the foot? If the output shaft had a defective seal, water could have gotten in and did all types of things to the brushes and windings in the foot. If, like you stated, that you read voltage from the battery all the way to the wires going down the shaft to the foot, was those readings purely static voltages and not while running? If you did read good reading to the foot, then you have to open up the foot and see what is going on in there. Could be as simple as a broken wire or more serious as open windings. But if everything else checks out, the foot holds the answer... Before I would open up the foot, I would try again in a few days of drying out and see first. But either way now, I see going into the foot for repairs. JMHO!