Golly..
I hope I can say what I want to... If you take a screw driver remove the "cap" of the trolling motor.. turn it over. There is often a small round plastic channel. Normally, there is part of the steering cable goes inside this and it moves the indicator arrow to show you which direction the motor is heading.
I have had part of this channel actually break causing the arrow NOT to move. I have also had part of the steering cable that enters this channel slide out causing the arrow not to move.
There is also a possibility that the steering cable itself has broken. If thathappens... the foot control pedal will be extremely loose and the motor will not turn.
I would almost consider the channel under the arrow is broken or the cable has slipped.
GOOD LUCK..