diff --git a/hddfancontrol/__init__.py b/hddfancontrol/__init__.py
index 6013da1..20761cc 100755
--- a/hddfancontrol/__init__.py
+++ b/hddfancontrol/__init__.py
@@ -97,6 +97,7 @@ class Drive:
     try:
       output = subprocess.check_output(cmd,
                                        stdin=subprocess.DEVNULL,
+                                       stderr=subprocess.STDOUT,
                                        universal_newlines=True)
     except subprocess.CalledProcessError:
       supported = False
diff --git a/tests/__init__.py b/tests/__init__.py
index bd44fbe..a84906e 100755
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -66,24 +66,28 @@ class TestDrive(unittest.TestCase):
       self.assertEqual(self.drive.supportsHitachiTempQuery(), True)
       subprocess_check_output_mock.assert_called_once_with(("hdparm", "-H", "/dev/sdz"),
                                                            stdin=subprocess.DEVNULL,
+                                                           stderr=subprocess.STDOUT,
                                                            universal_newlines=True)
     with unittest.mock.patch("hddfancontrol.subprocess.check_output") as subprocess_check_output_mock:
       subprocess_check_output_mock.return_value = "\n/dev/sdz:\nSG_IO: questionable sense data, results may be incorrect\n drive temperature (celsius) is: -18\n drive temperature in range: yes"
       self.assertEqual(self.drive.supportsHitachiTempQuery(), False)
       subprocess_check_output_mock.assert_called_once_with(("hdparm", "-H", "/dev/sdz"),
                                                            stdin=subprocess.DEVNULL,
+                                                           stderr=subprocess.STDOUT,
                                                            universal_newlines=True)
     with unittest.mock.patch("hddfancontrol.subprocess.check_output") as subprocess_check_output_mock:
       subprocess_check_output_mock.return_value = "\n/dev/sdz:\nSG_IO: missing sense data, results may be incorrect\n drive temperature (celsius) is: -18\n drive temperature in range: yes"
       self.assertEqual(self.drive.supportsHitachiTempQuery(), False)
       subprocess_check_output_mock.assert_called_once_with(("hdparm", "-H", "/dev/sdz"),
                                                            stdin=subprocess.DEVNULL,
+                                                           stderr=subprocess.STDOUT,
                                                            universal_newlines=True)
     with unittest.mock.patch("hddfancontrol.subprocess.check_output") as subprocess_check_output_mock:
       subprocess_check_output_mock.return_value = "\n/dev/sdz:\nSG_IO: bad/missing sense data, sb[]: 70 00 05 00 00 00 00 0a 04 51 40 00 21 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n drive temperature (celsius) is: -18\n drive temperature in range: yes"
       self.assertEqual(self.drive.supportsHitachiTempQuery(), False)
       subprocess_check_output_mock.assert_called_once_with(("hdparm", "-H", "/dev/sdz"),
                                                            stdin=subprocess.DEVNULL,
+                                                           stderr=subprocess.STDOUT,
                                                            universal_newlines=True)
 
   def test_getState(self):