diff --git a/library/system/service b/library/system/service
index e83bd19982..f0b330bffd 100644
--- a/library/system/service
+++ b/library/system/service
@@ -694,7 +694,14 @@ class FreeBsdService(Service):
             if os.path.isfile(rcfile):
                 self.rcconf_file = rcfile
 
-        self.rcconf_key = "%s_enable" % self.name
+        rc, stdout, stderr = self.execute_command("%s %s %s %s" % (self.svc_cmd, self.name, 'rcvar', self.arguments))
+        rcvars = shlex.split(stdout, comments=True)
+        if not rcvars:
+            self.module.fail_json(msg="unable to determine rcvar")
+
+        # In rare cases, i.e. sendmail, rcvar can return several key=value pairs
+        # Usually there is just one, however.
+        self.rcconf_key = rcvars[0].split('=')[0]
 
         return self.service_enable_rcconf()