I had a customer blow a solenoid last month and I just got around to fixing it tonight. Wiring is one aspect I don't enjoy dealing with in this job. There are so many variables. First I checked the connections to make sure it wasn't a loose wire. Then you check to see if it is one of the channels on the timer that's out. Then you check to make sure it's not the wire. Then you check to make sure it's not the valve. Then, then you replace the solenoid and you hope that solves it. Which it did. All in all it took an hour.