diff --git a/Marlin/src/Marlin.cpp b/Marlin/src/Marlin.cpp
index eb05267872..4add62ff72 100644
--- a/Marlin/src/Marlin.cpp
+++ b/Marlin/src/Marlin.cpp
@@ -62,6 +62,10 @@
   #include "feature/digipot/digipot.h"
 #endif
 
+#if ENABLED(MIXING_EXTRUDER)
+  #include "feature/mixing.h"
+#endif
+
 #if ENABLED(BEZIER_CURVE_SUPPORT)
   #include "module/planner_bezier.h"
 #endif
@@ -186,13 +190,6 @@ millis_t max_inactive_time = 0,
   AdvancedPauseMenuResponse advanced_pause_menu_response;
 #endif
 
-#if ENABLED(MIXING_EXTRUDER)
-  float mixing_factor[MIXING_STEPPERS]; // Reciprocal of mix proportion. 0.0 = off, otherwise >= 1.0.
-  #if MIXING_VIRTUAL_TOOLS > 1
-    float mixing_virtual_tool_mix[MIXING_VIRTUAL_TOOLS][MIXING_STEPPERS];
-  #endif
-#endif
-
 #ifdef CHDK
   millis_t chdkHigh = 0;
   bool chdkActive = false;
@@ -302,45 +299,6 @@ void suicide() {
 
 #endif
 
-#if ENABLED(MIXING_EXTRUDER)
-
-  void normalize_mix() {
-    float mix_total = 0.0;
-    for (uint8_t i = 0; i < MIXING_STEPPERS; i++) mix_total += RECIPROCAL(mixing_factor[i]);
-    // Scale all values if they don't add up to ~1.0
-    if (!NEAR(mix_total, 1.0)) {
-      SERIAL_PROTOCOLLNPGM("Warning: Mix factors must add up to 1.0. Scaling.");
-      for (uint8_t i = 0; i < MIXING_STEPPERS; i++) mixing_factor[i] *= mix_total;
-    }
-  }
-
-  #if ENABLED(DIRECT_MIXING_IN_G1)
-    // Get mixing parameters from the GCode
-    // The total "must" be 1.0 (but it will be normalized)
-    // If no mix factors are given, the old mix is preserved
-    void gcode_get_mix() {
-      const char* mixing_codes = "ABCDHI";
-      byte mix_bits = 0;
-      for (uint8_t i = 0; i < MIXING_STEPPERS; i++) {
-        if (parser.seenval(mixing_codes[i])) {
-          SBI(mix_bits, i);
-          float v = parser.value_float();
-          NOLESS(v, 0.0);
-          mixing_factor[i] = RECIPROCAL(v);
-        }
-      }
-      // If any mixing factors were included, clear the rest
-      // If none were included, preserve the last mix
-      if (mix_bits) {
-        for (uint8_t i = 0; i < MIXING_STEPPERS; i++)
-          if (!TEST(mix_bits, i)) mixing_factor[i] = 0.0;
-        normalize_mix();
-      }
-    }
-  #endif
-
-#endif
-
 /**************************************************
  ***************** GCode Handlers *****************
  **************************************************/
@@ -362,16 +320,6 @@ void quickstop_stepper() {
   SYNC_PLAN_POSITION_KINEMATIC();
 }
 
-#if ENABLED(MIXING_EXTRUDER)
-  #include "gcode/feature/mixing/M163.h"
-  #if MIXING_VIRTUAL_TOOLS > 1
-    #include "gcode/feature/mixing/M164.h"
-  #endif
-  #if ENABLED(DIRECT_MIXING_IN_G1)
-    #include "gcode/feature/mixing/M165.h"
-  #endif
-#endif
-
 #include "gcode/control/M999.h"
 
 #include "gcode/control/T.h"
@@ -957,12 +905,7 @@ void setup() {
   #endif
 
   #if ENABLED(MIXING_EXTRUDER) && MIXING_VIRTUAL_TOOLS > 1
-    // Initialize mixing to 100% color 1
-    for (uint8_t i = 0; i < MIXING_STEPPERS; i++)
-      mixing_factor[i] = (i == 0) ? 1.0 : 0.0;
-    for (uint8_t t = 0; t < MIXING_VIRTUAL_TOOLS; t++)
-      for (uint8_t i = 0; i < MIXING_STEPPERS; i++)
-        mixing_virtual_tool_mix[t][i] = mixing_factor[i];
+    mixing_tools_init();
   #endif
 
   #if ENABLED(BLTOUCH)
diff --git a/Marlin/src/Marlin.h b/Marlin/src/Marlin.h
index ba37ccd598..97e80c5db7 100644
--- a/Marlin/src/Marlin.h
+++ b/Marlin/src/Marlin.h
@@ -223,13 +223,6 @@ extern millis_t max_inactive_time, stepper_inactive_time;
   extern int lpq_len;
 #endif
 
-#if ENABLED(MIXING_EXTRUDER)
-  extern float mixing_factor[MIXING_STEPPERS];
-  #if MIXING_VIRTUAL_TOOLS > 1
-    extern float mixing_virtual_tool_mix[MIXING_VIRTUAL_TOOLS][MIXING_STEPPERS];
-  #endif
-#endif
-
 void calculate_volumetric_multipliers();
 
 bool pin_is_protected(const int8_t pin);
diff --git a/Marlin/src/feature/mixing.cpp b/Marlin/src/feature/mixing.cpp
new file mode 100644
index 0000000000..7300c3e28a
--- /dev/null
+++ b/Marlin/src/feature/mixing.cpp
@@ -0,0 +1,79 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "../inc/MarlinConfig.h"
+
+#if ENABLED(MIXING_EXTRUDER)
+
+float mixing_factor[MIXING_STEPPERS]; // Reciprocal of mix proportion. 0.0 = off, otherwise >= 1.0.
+
+#if MIXING_VIRTUAL_TOOLS > 1
+
+  float mixing_virtual_tool_mix[MIXING_VIRTUAL_TOOLS][MIXING_STEPPERS];
+
+  void mixing_tools_init() {
+    // Initialize mixing to 100% color 1
+    for (uint8_t i = 0; i < MIXING_STEPPERS; i++)
+      mixing_factor[i] = (i == 0) ? 1.0 : 0.0;
+    for (uint8_t t = 0; t < MIXING_VIRTUAL_TOOLS; t++)
+      for (uint8_t i = 0; i < MIXING_STEPPERS; i++)
+        mixing_virtual_tool_mix[t][i] = mixing_factor[i];
+  }
+
+#endif // MIXING_VIRTUAL_TOOLS > 1
+
+void normalize_mix() {
+  float mix_total = 0.0;
+  for (uint8_t i = 0; i < MIXING_STEPPERS; i++) mix_total += RECIPROCAL(mixing_factor[i]);
+  // Scale all values if they don't add up to ~1.0
+  if (!NEAR(mix_total, 1.0)) {
+    SERIAL_PROTOCOLLNPGM("Warning: Mix factors must add up to 1.0. Scaling.");
+    for (uint8_t i = 0; i < MIXING_STEPPERS; i++) mixing_factor[i] *= mix_total;
+  }
+}
+
+#if ENABLED(DIRECT_MIXING_IN_G1)
+  // Get mixing parameters from the GCode
+  // The total "must" be 1.0 (but it will be normalized)
+  // If no mix factors are given, the old mix is preserved
+  void gcode_get_mix() {
+    const char mixing_codes[] = { 'A', 'B', 'C', 'D', 'H', 'I' };
+    byte mix_bits = 0;
+    for (uint8_t i = 0; i < MIXING_STEPPERS; i++) {
+      if (parser.seenval(mixing_codes[i])) {
+        SBI(mix_bits, i);
+        float v = parser.value_float();
+        NOLESS(v, 0.0);
+        mixing_factor[i] = RECIPROCAL(v);
+      }
+    }
+    // If any mixing factors were included, clear the rest
+    // If none were included, preserve the last mix
+    if (mix_bits) {
+      for (uint8_t i = 0; i < MIXING_STEPPERS; i++)
+        if (!TEST(mix_bits, i)) mixing_factor[i] = 0.0;
+      normalize_mix();
+    }
+  }
+#endif
+
+#endif // MIXING_EXTRUDER
diff --git a/Marlin/src/feature/mixing.h b/Marlin/src/feature/mixing.h
new file mode 100644
index 0000000000..fff240c0e0
--- /dev/null
+++ b/Marlin/src/feature/mixing.h
@@ -0,0 +1,41 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef __MIXING_H__
+#define __MIXING_H__
+
+#include "../inc/MarlinConfig.h"
+
+extern float mixing_factor[MIXING_STEPPERS]; // Reciprocal of mix proportion. 0.0 = off, otherwise >= 1.0.
+
+#if MIXING_VIRTUAL_TOOLS > 1
+  extern float mixing_virtual_tool_mix[MIXING_VIRTUAL_TOOLS][MIXING_STEPPERS];
+  void mixing_tools_init();
+#endif
+
+void normalize_mix();
+
+#if ENABLED(DIRECT_MIXING_IN_G1)
+  void gcode_get_mix();
+#endif
+
+#endif // __MIXING_H__
diff --git a/Marlin/src/gcode/feature/mixing/M163.h b/Marlin/src/gcode/feature/mixing/M163.cpp
similarity index 87%
rename from Marlin/src/gcode/feature/mixing/M163.h
rename to Marlin/src/gcode/feature/mixing/M163.cpp
index 5dd8df4815..721928289e 100644
--- a/Marlin/src/gcode/feature/mixing/M163.h
+++ b/Marlin/src/gcode/feature/mixing/M163.cpp
@@ -20,6 +20,13 @@
  *
  */
 
+#include "../../../inc/MarlinConfig.h"
+
+#if ENABLED(MIXING_EXTRUDER)
+
+#include "../../gcode.h"
+#include "../../../feature/mixing.h"
+
 /**
  * M163: Set a single mix factor for a mixing extruder
  *       This is called "weight" by some systems.
@@ -28,7 +35,7 @@
  *   P[float]   The mix value
  *
  */
-void gcode_M163() {
+void GcodeSuite::M163() {
   const int mix_index = parser.intval('S');
   if (mix_index < MIXING_STEPPERS) {
     float mix_value = parser.floatval('P');
@@ -36,3 +43,5 @@ void gcode_M163() {
     mixing_factor[mix_index] = RECIPROCAL(mix_value);
   }
 }
+
+#endif // MIXING_EXTRUDER
diff --git a/Marlin/src/gcode/feature/mixing/M164.h b/Marlin/src/gcode/feature/mixing/M164.cpp
similarity index 83%
rename from Marlin/src/gcode/feature/mixing/M164.h
rename to Marlin/src/gcode/feature/mixing/M164.cpp
index 07176766db..138b374fd9 100644
--- a/Marlin/src/gcode/feature/mixing/M164.h
+++ b/Marlin/src/gcode/feature/mixing/M164.cpp
@@ -20,13 +20,20 @@
  *
  */
 
+#include "../../../inc/MarlinConfig.h"
+
+#if ENABLED(MIXING_EXTRUDER) && MIXING_VIRTUAL_TOOLS > 1
+
+#include "../../gcode.h"
+#include "../../../feature/mixing.h"
+
 /**
  * M164: Store the current mix factors as a virtual tool.
  *
  *   S[index]   The virtual tool to store
  *
  */
-void gcode_M164() {
+void GcodeSuite::M164() {
   const int tool_index = parser.intval('S');
   if (tool_index < MIXING_VIRTUAL_TOOLS) {
     normalize_mix();
@@ -34,3 +41,5 @@ void gcode_M164() {
       mixing_virtual_tool_mix[tool_index][i] = mixing_factor[i];
   }
 }
+
+#endif // MIXING_EXTRUDER && MIXING_VIRTUAL_TOOLS > 1
diff --git a/Marlin/src/gcode/feature/mixing/M165.h b/Marlin/src/gcode/feature/mixing/M165.cpp
similarity index 86%
rename from Marlin/src/gcode/feature/mixing/M165.h
rename to Marlin/src/gcode/feature/mixing/M165.cpp
index 4c75891295..feaa8248ee 100644
--- a/Marlin/src/gcode/feature/mixing/M165.h
+++ b/Marlin/src/gcode/feature/mixing/M165.cpp
@@ -20,6 +20,13 @@
  *
  */
 
+#include "../../../inc/MarlinConfig.h"
+
+#if ENABLED(DIRECT_MIXING_IN_G1)
+
+#include "../../gcode.h"
+#include "../../../feature/mixing.h"
+
 /**
  * M165: Set multiple mix factors for a mixing extruder.
  *       Factors that are left out will be set to 0.
@@ -33,4 +40,6 @@
  *   I[factor] Mix factor for extruder stepper 6
  *
  */
-void gcode_M165() { gcode_get_mix(); }
+void GcodeSuite::M165() { gcode_get_mix(); }
+
+#endif // DIRECT_MIXING_IN_G1
diff --git a/Marlin/src/gcode/gcode.cpp b/Marlin/src/gcode/gcode.cpp
index 065bf1fe26..ee68d5a77e 100644
--- a/Marlin/src/gcode/gcode.cpp
+++ b/Marlin/src/gcode/gcode.cpp
@@ -116,9 +116,6 @@ void GcodeSuite::dwell(millis_t time) {
 //
 // Placeholders for non-migrated codes
 //
-extern void gcode_M163();
-extern void gcode_M164();
-extern void gcode_M165();
 extern void gcode_M999();
 extern void gcode_T(uint8_t tmp_extruder);
 
@@ -462,18 +459,12 @@ void GcodeSuite::process_next_command() {
       #endif
 
       #if ENABLED(MIXING_EXTRUDER)
-        case 163: // M163: Set a component weight for mixing extruder
-          gcode_M163();
-          break;
+        case 163: M163(); break;    // M163: Set a component weight for mixing extruder
         #if MIXING_VIRTUAL_TOOLS > 1
-          case 164: // M164: Save current mix as a virtual extruder
-            gcode_M164();
-            break;
+          case 164: M164(); break;  // M164: Save current mix as a virtual extruder
         #endif
         #if ENABLED(DIRECT_MIXING_IN_G1)
-          case 165: // M165: Set multiple mix weights
-            gcode_M165();
-            break;
+          case 165: M165(); break;  // M165: Set multiple mix weights
         #endif
       #endif
 
diff --git a/Marlin/src/module/planner.cpp b/Marlin/src/module/planner.cpp
index 1dc983c334..f906f769ea 100644
--- a/Marlin/src/module/planner.cpp
+++ b/Marlin/src/module/planner.cpp
@@ -80,6 +80,10 @@
   #include "../feature/baricuda.h"
 #endif
 
+#if ENABLED(MIXING_EXTRUDER)
+  #include "../feature/mixing.h"
+#endif
+
 Planner planner;
 
   // public:
diff --git a/Marlin/src/module/tool_change.cpp b/Marlin/src/module/tool_change.cpp
index b8fab7cc80..68b8d82eaa 100644
--- a/Marlin/src/module/tool_change.cpp
+++ b/Marlin/src/module/tool_change.cpp
@@ -42,6 +42,10 @@
   #include "../feature/snmm.h"
 #endif
 
+#if ENABLED(MIXING_EXTRUDER)
+  #include "../feature/mixing.h"
+#endif
+
 #if ENABLED(SWITCHING_EXTRUDER)
 
   #if EXTRUDERS > 3