Jay you had me until the last sentence …. Never ever just replace parts because they are cheap and go bad often. Troubleshoot the issue and replace parts when the diagnosis supports replacing a part. The shotgun process will end up costing you more than the cheap part and you will likely still have a broken plane.
Thanks for the input. It is great, in theory. I'm guessing you've never had to make a schedule or get equipment up and running in which the per minute down time cost 10x the price of the part?
Diagnosing and isolating the faulty component is key to solving the underlying problem. But intermittent issues don't always allow for solid data gathering. One has to use wisdom and experience to assign most likely causes. So if this was a plane that needed to fly, and was having intermittent start issues, and via testing and symptom analysis one has isolated the potential failed component to two relays, then someone that sees the big and small picture will throw two relays (solenoids) at it.
Failures are usually one single component, and it's always better to spend an extra hour or two troubleshooting and reviewing all technical manuals/diagrams/etc, but some times is crap or get off the pot.
