diff --git a/Marlin/endstops.cpp b/Marlin/endstops.cpp
index b0a1afe4b4..5349270552 100644
--- a/Marlin/endstops.cpp
+++ b/Marlin/endstops.cpp
@@ -719,3 +719,114 @@ void Endstops::update() {
     }
   }
 } // Endstops::update()
+
+#if ENABLED(PINS_DEBUGGING)
+
+  bool Endstops::monitor_flag = false;
+
+  /**
+   * monitors endstops & Z probe for changes
+   *
+   * If a change is detected then the LED is toggled and
+   * a message is sent out the serial port
+   *
+   * Yes, we could miss a rapid back & forth change but
+   * that won't matter because this is all manual.
+   *
+   */
+  void Endstops::monitor() {
+
+    static uint16_t old_live_state_local = 0;
+    static uint8_t local_LED_status = 0;
+    uint16_t live_state_local = 0;
+
+    #if HAS_X_MIN
+      if (READ(X_MIN_PIN)) SBI(live_state_local, X_MIN);
+    #endif
+    #if HAS_X_MAX
+      if (READ(X_MAX_PIN)) SBI(live_state_local, X_MAX);
+    #endif
+    #if HAS_Y_MIN
+      if (READ(Y_MIN_PIN)) SBI(live_state_local, Y_MIN);
+    #endif
+    #if HAS_Y_MAX
+      if (READ(Y_MAX_PIN)) SBI(live_state_local, Y_MAX);
+    #endif
+    #if HAS_Z_MIN
+      if (READ(Z_MIN_PIN)) SBI(live_state_local, Z_MIN);
+    #endif
+    #if HAS_Z_MAX
+      if (READ(Z_MAX_PIN)) SBI(live_state_local, Z_MAX);
+    #endif
+    #if HAS_Z_MIN_PROBE_PIN
+      if (READ(Z_MIN_PROBE_PIN)) SBI(live_state_local, Z_MIN_PROBE);
+    #endif
+    #if HAS_X2_MIN
+      if (READ(X2_MIN_PIN)) SBI(live_state_local, X2_MIN);
+    #endif
+    #if HAS_X2_MAX
+      if (READ(X2_MAX_PIN)) SBI(live_state_local, X2_MAX);
+    #endif
+    #if HAS_Y2_MIN
+      if (READ(Y2_MIN_PIN)) SBI(live_state_local, Y2_MIN);
+    #endif
+    #if HAS_Y2_MAX
+      if (READ(Y2_MAX_PIN)) SBI(live_state_local, Y2_MAX);
+    #endif
+    #if HAS_Z2_MIN
+      if (READ(Z2_MIN_PIN)) SBI(live_state_local, Z2_MIN);
+    #endif
+    #if HAS_Z2_MAX
+      if (READ(Z2_MAX_PIN)) SBI(live_state_local, Z2_MAX);
+    #endif
+
+    uint16_t endstop_change = live_state_local ^ old_live_state_local;
+
+    if (endstop_change) {
+      #if HAS_X_MIN
+        if (TEST(endstop_change, X_MIN)) SERIAL_PROTOCOLPAIR("  X_MIN:", TEST(live_state_local, X_MIN));
+      #endif
+      #if HAS_X_MAX
+        if (TEST(endstop_change, X_MAX)) SERIAL_PROTOCOLPAIR("  X_MAX:", TEST(live_state_local, X_MAX));
+      #endif
+      #if HAS_Y_MIN
+        if (TEST(endstop_change, Y_MIN)) SERIAL_PROTOCOLPAIR("  Y_MIN:", TEST(live_state_local, Y_MIN));
+      #endif
+      #if HAS_Y_MAX
+        if (TEST(endstop_change, Y_MAX)) SERIAL_PROTOCOLPAIR("  Y_MAX:", TEST(live_state_local, Y_MAX));
+      #endif
+      #if HAS_Z_MIN
+        if (TEST(endstop_change, Z_MIN)) SERIAL_PROTOCOLPAIR("  Z_MIN:", TEST(live_state_local, Z_MIN));
+      #endif
+      #if HAS_Z_MAX
+        if (TEST(endstop_change, Z_MAX)) SERIAL_PROTOCOLPAIR("  Z_MAX:", TEST(live_state_local, Z_MAX));
+      #endif
+      #if HAS_Z_MIN_PROBE_PIN
+        if (TEST(endstop_change, Z_MIN_PROBE)) SERIAL_PROTOCOLPAIR("  PROBE:", TEST(live_state_local, Z_MIN_PROBE));
+      #endif
+      #if HAS_X2_MIN
+        if (TEST(endstop_change, X2_MIN)) SERIAL_PROTOCOLPAIR("  X2_MIN:", TEST(live_state_local, X2_MIN));
+      #endif
+      #if HAS_X2_MAX
+        if (TEST(endstop_change, X2_MAX)) SERIAL_PROTOCOLPAIR("  X2_MAX:", TEST(live_state_local, X2_MAX));
+      #endif
+      #if HAS_Y2_MIN
+        if (TEST(endstop_change, Y2_MIN)) SERIAL_PROTOCOLPAIR("  Y2_MIN:", TEST(live_state_local, Y2_MIN));
+      #endif
+      #if HAS_Y2_MAX
+        if (TEST(endstop_change, Y2_MAX)) SERIAL_PROTOCOLPAIR("  Y2_MAX:", TEST(live_state_local, Y2_MAX));
+      #endif
+      #if HAS_Z2_MIN
+        if (TEST(endstop_change, Z2_MIN)) SERIAL_PROTOCOLPAIR("  Z2_MIN:", TEST(live_state_local, Z2_MIN));
+      #endif
+      #if HAS_Z2_MAX
+        if (TEST(endstop_change, Z2_MAX)) SERIAL_PROTOCOLPAIR("  Z2_MAX:", TEST(live_state_local, Z2_MAX));
+      #endif
+      SERIAL_PROTOCOLPGM("\n\n");
+      analogWrite(LED_PIN, local_LED_status);
+      local_LED_status ^= 255;
+      old_live_state_local = live_state_local;
+    }
+  }
+
+#endif // PINS_DEBUGGING