you have to get that z endstop to say open when not pressed and triggered when it is
ie
just use m119 with z endstop switch not pressed, should say open
repeat use m119 with z endstop switched pressed, should say triggered.
If its reverse of what it should be but is actually changing, you need to invert z min endstop in firmware
see Z_MIN_ENDSTOP_INVERTING in configuration .h (if its true make it false and if false make it true)
if it does not change you have a fault you will need to fix it or work around it, try moving a working endstop from the xmin pins to the zmin pins and rerun tests remembering to press x endstop and watch for change in z min). If it works its just your endstop. if not its your ramps or mega (presuming you have a ramps, I cant recall)
Now move you x endstop back onto the xmin pins, before you forget
ie
just use m119 with z endstop switch not pressed, should say open
repeat use m119 with z endstop switched pressed, should say triggered.
If its reverse of what it should be but is actually changing, you need to invert z min endstop in firmware
see Z_MIN_ENDSTOP_INVERTING in configuration .h (if its true make it false and if false make it true)
if it does not change you have a fault you will need to fix it or work around it, try moving a working endstop from the xmin pins to the zmin pins and rerun tests remembering to press x endstop and watch for change in z min). If it works its just your endstop. if not its your ramps or mega (presuming you have a ramps, I cant recall)
Now move you x endstop back onto the xmin pins, before you forget