diff --git a/Makefile.am b/Makefile.am
index 610e543..30223d0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -6,7 +6,8 @@
 phosphor_fan_presence_tach_SOURCES = \
 	fan_enclosure.cpp \
 	tach_sensor.cpp \
-	tach_detect.cpp
+	tach_detect.cpp \
+	utility.cpp
 nodist_phosphor_fan_presence_tach_SOURCES = \
 	fan_detect_defs.cpp