diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index 80f7950ea2..3f01a88f02 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -1771,6 +1771,7 @@
  */
 //#define FILAMENT_RUNOUT_SENSOR
 #if ENABLED(FILAMENT_RUNOUT_SENSOR)
+  //#define NUM_RUNOUT_SENSORS 1      // Number of sensors, up to one per extruder. Define a FIL_RUNOUT#_PIN for each.
   #define FIL_RUNOUT_ENABLED { true } // Default enabled state for sensors E0[, E1[, E2[, E3...]]]. Override with M591 followed by M500.
   #define FIL_RUNOUT_MODE    { 1 }    // Default mode for sensors E0[, E1[, E2[, E3...]]]. 0:NONE  1:Switch NO  2:Switch NC  7:Motion Sensor
   #define FIL_RUNOUT_PULLUP           // Use internal pullup for filament runout pins.
diff --git a/buildroot/tests/rambo b/buildroot/tests/rambo
index de6cdc7129..a2c99efec0 100644
--- a/buildroot/tests/rambo
+++ b/buildroot/tests/rambo
@@ -15,7 +15,7 @@ opt_set MOTHERBOARD BOARD_RAMBO \
         TEMP_SENSOR_PROBE 1 TEMP_PROBE_PIN 12 \
         TEMP_SENSOR_CHAMBER 3 TEMP_CHAMBER_PIN 3 HEATER_CHAMBER_PIN 45 \
         GRID_MAX_POINTS_X 16 AUTO_POWER_E_TEMP 80 \
-        FANMUX0_PIN 53
+        FANMUX0_PIN 53 NUM_RUNOUT_SENSORS 1
 opt_disable Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN USE_WATCHDOG
 opt_enable USE_ZMAX_PLUG REPRAP_DISCOUNT_SMART_CONTROLLER LCD_PROGRESS_BAR LCD_PROGRESS_BAR_TEST \
            FIX_MOUNTED_PROBE CODEPENDENT_XY_HOMING PIDTEMPBED PTC_PROBE PTC_BED \