diff --git a/libraries/AP_RangeFinder/AP_RangeFinder.cpp b/libraries/AP_RangeFinder/AP_RangeFinder.cpp
index 237333f6b7..f91d06af33 100644
--- a/libraries/AP_RangeFinder/AP_RangeFinder.cpp
+++ b/libraries/AP_RangeFinder/AP_RangeFinder.cpp
@@ -54,6 +54,7 @@
 
 #include <AP_BoardConfig/AP_BoardConfig.h>
 #include <AP_Logger/AP_Logger.h>
+#include <AP_SerialManager/AP_SerialManager.h>
 #include <AP_Vehicle/AP_Vehicle_Type.h>
 
 extern const AP_HAL::HAL &hal;