I pulled the trolling motor's control head apart and the female spade connectors on the battery wires were lunched. The only thing holding the one together was the shrink tubing and the other was loose as a goose on it's terminal - connectors on the motor wires are in good shape as are the male tabs on the speed control.

I'll solder on new females and test it - should be OK then.

The culprit(s).