I would expect a longer period than 9 yrs if only used 3 4 times a year on say 5 site per trip.
Check batteries in remote:
Check battery the mover is powered from
Has it been serviced in the 9yrs of it's life?
If not the it could be a motor problem.
I'm not brilliant at reversing and I've been drawing trailers on BT (now retired) a pain reversing.
Bob
August 2009