In other words: In "Test Mode 4" if you enter a component's code (say 3-4-3 for example:) the system will go test that component electronically (you might hear a "Click" as it triggers the solenoid) and then if the component passes the test the LED light will respond with a positive flash. If the component fails the test you won't get a LED flash response. Try a few different components and see how it responds. Like try testing solenoid S-1 and see how it responds, you should get the same response if solenoid S-2 is tested. This will reaffirm your previous suspicions that the S-2 solenoid is AFU. Good luck ....... Mike