Your bed.g file looks OK. Do you have a M671 command in config.g defining the positions of your leadscrews?

@dc42 said in z axis random reverse homing:
I don't understand...
-wires checked ok
-switched z motors to x and y connectors they work
-plugged x motor in to z plug plus jumpers in the unused z connector it work ( switched between z1 and z2 connectors +jumpers ---all ok)
-plugged x and y motors in to both z connectors ----just one work when i home Z (no sense!!)
-plugged both z motors in to both z connectors homing z -----1 motor go fast 1 motor go slow (O.o)
NOW:
i have reduced M203 in config.g for Z to 900
i have reduced in homez.g and in homeall.g F to 250 for z

ALL WORKS

thanks for the help if other strange things happen I will let you know