diff --git a/include/field_door.h b/include/field_door.h
index dd039a5c2b..8b4955cacd 100644
--- a/include/field_door.h
+++ b/include/field_door.h
@@ -22,6 +22,5 @@ s8 FieldAnimateDoorClose(u32, u32);
 s8 FieldAnimateDoorOpen(u32, u32);
 bool8 FieldIsDoorAnimationRunning(void);
 u32 GetDoorSoundEffect(u32 x, u32 y);
-bool8 sub_808A964(void);
 
 #endif
diff --git a/src/field_door.c b/src/field_door.c
index 38c0312648..f73c6bb55f 100644
--- a/src/field_door.c
+++ b/src/field_door.c
@@ -9,6 +9,8 @@
 #include "constants/maps.h"
 #include "task.h"
 
+bool8 sub_808A964(void);
+
 const u8 DoorAnimTiles_04[][0x100] =
 {
     INCBIN_U8("graphics/door_anims/04/0.4bpp"),