Robin2:
Try one the examples in this Simple Stepper Code to determine if the motor works correctly with simple code. If not then it is unlikely to work with GRBL.You say "UniversalGcodeSender: I't my favourite". Does that mean that you have another Arduino project using GCodeSender and GRBL that is working properly?
...R
Stepper Motor Basics
Thanks for the answer.
I prefer UGS just because the "go home" button work fine (in the Grbl controller it don't work , so i can't do the homing).
I try the exemple but the stepper don't seems to move correctly 
I don't know if it is right but i follow this connections (http://howtomechatronics.com/wp-content/uploads/2015/08/A4988-Wiring-Diagram.png?x57244) and the result is this:
Is it ok? Or there is some problem?