Hi everyone, does anyone already have this problem ?  I've two motor on y axis , A  motor slave to Y .  I've independent home switch for each motor . When engage homing, only A motor turn .. ( its like  if the 2 motor are not slave , but on jog , they works good ) .. need help  pleese !

I'm having same problem, anyone have a solution?

Sounds like you need to edit the button script for Ref all Home.

DoButton(24) will home the Z axis.
DoButton(22) will home the X axis.
RefCombination(9) will home the Y and A axis together.

Tweakie.

I'll try that when i get home. In my case i dont have independent homing switches for y and a. Will it still work? Or should i put in a switch ...which i dont want to do since then the gantry will wrack out of square is the switxhes aren't perfectly aligned.

I use these proximity sensors on my Y and A axis. https://makerparts.ca/collections/power-control/products/6-36vdc-proximity-sensor?variant=13689184516

By turning the lock nuts you can micro adjust the projection of the sensor so that your gantry auto squares every time you home. CNCRouterParts has a good video showing this in action and the theory is covered in many threads here.