Z axis - how to allow minus direction Arduino Sprinter

//-----------------------------------------------------------------------
//// ENDSTOP SETTINGS:
//-----------------------------------------------------------------------
// Sets direction of endstops when homing; 1=MAX, -1=MIN
#define X_HOME_DIR -1
#define Y_HOME_DIR -1
#define Z_HOME_DIR -1

//#define ENDSTOPS_ONLY_FOR_HOMING // If defined the endstops will only be used for homing <-- Uncomment this

const bool min_software_endstops = false; //If true, axis won't move to coordinates less than zero.  <-- Make sure this is set to false
const bool max_software_endstops = true; //If true, axis won't move to coordinates greater than the defined lengths below.