that green LED should be marked as V66.
if this is correct then...

If any input from the 1S2(drive switch), 1S3(inching switch), 7S22(brake switch) or 2S7(lift limit switch) switches are detected that light should go from flashing to solid for approximately 2 seconds and then flashes again.
If it never pauses for the 2 seconds as described above then you have an input signal problem.
I would say that there is a signal input problem from the control handle.
Check the wiring, connectors etc and make sure there are no faulty connections or bad wires.
Double check that the switch at the base of the handle arm where it meets the drive unit is operating properly when the handle is pulled down. If that switch is not working then you will have no function.