@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