Diagnostics is not as difficult as most techs make out it is. Being on commission tends to have them looking at the most expensive options first. Many times I have repaired a problem with a visual inspection of the item in question. That is why I always say “start with the basics” it can save a lot of headaches. Sure with the computer controlled systems of today there are many times when only an experienced tech can find the problem. But before going that route do a visual inspection, looking for such things as a disconnected wire or hose corrosion or excessive grease or dirt where it would not normally be. Just use some common sense it can go a long way. I cannot stress enough checking the battery, both positive and negative, also where the negative attaches to the body for corrosion. If it accessible check the ground for the item in question they can be hidden and I think the manufacture does this on purpose. I suggest removing the battery terminals and they should be shiny without a hint of corrosion. The same with the ground connections I always clean them no matter how clean they look.It also is a good idea to check for correct voltage as it is critical to the operation of many systems as the required voltage drops some as low as .5 volts. Ford and all magnetic starters require battery voltage to perform correctly be sure to check this at the starter as well as the battery wires and battery cables can have internal corrosion that is hard to see and can cause many problems. Engine will not crankIf you hear a click- Corrosion- Battery voltage and condition- Voltage at the battery and starterNo click- Ignition switch engaging the starter- Neutral safety switchLoud thunk- Locked up engine or stuck starterNo start- Spark (you have to have spark to have fuel pressure)- Fuel, pressure and quantity- Timing, valve and ignitionThis is brief chart