Step 8: Test
Testing is the best predictor of customer satisfaction. If the symptom you obtained in step 2 and reproduced in step 4 is now gone, and no new problems have occurred, its likely the customer will be happy. Most customer relations horror stories occur when testing was inadequate or non-existent. When you test, ask these four quality questions:
Much of the testing may be done while the system is partially disassembled, but it's important to do a final test after it's entirely reassembled so there are no unpleasant surprises for the customer.
Since an intermittent occurs randomly and can't be forced to occur by a specific procedure, you can't be certain the symptom went away. That's why it's so vital during Step 4, Symptom Reproduction, that you record how often it happens and what situations tend to increase its probability. If it occurred once per hour before, and you were unable to reproduce it after 2 days in testing, there's a high likelihood it's fixed. A testing period of a couple hours just wouldn't be sufficient. Most troubleshooters have a place where they can test an intermittent system without disrupting their other work.
Sometimes it's not practical to tie up technical personnel for the time it takes to test an intermittent. In such cases it's acceptable to have the customer assume the testing role as long as he or she is informed of it, consents to it, and understands that if the problem recurs the technician will cheerfully resume the troubleshooting process.