I have an 80lb A/P around 4 years old it has a habit of suddenly switching itself off, no power to foot pedal or auto pilot , yet the battery test light will work so no problem with power to the unit, Then after a little while it will all come back to life.
Cheers
Sean

Boating - Minn Kota - Riptide St Saltwater 80 Bow Mount Trolling Motor