OK, here is a DUMB ASS cobblers way around this. My machine homes in Z first. it looks for the switch to set the backs off until switch is unset.
The switch set and then unset is IMPORTANT. Mach3 is expecting the change.
My machine then homes Y axis, IF you don't care where Y axis home is then assign a switch to it and when it is trying to find home, trip the switch, after it reverses to untrip the switch manually untrip the switch. (let go!)
It will think Y is homed and proceed to home Z axis.
Any switch that can be easily reached by the operator can be used. I suggest to use the x-axis switch again.
Mach 3 allows ALL LIMIT switches and homing switches to be the same input. And that is what I do. so, if I trip any limit switch when it is homing in any axis, Mach3 thinks it has reached home and reverses the axis drive until the switch unsets.
Is this the BEST SOLUTION. I'm sure NOT. but it will work for now. Just make sure you config a home switch for Y. like you nhave foe X and Z.
so Mach 3 has something to look for and find when you trip it manually.