Please take these comments from a 30 year veteran of electronics testing as constructive comments:
Your assumption in step 1.3 is incorrect.
You SHOULD read battery voltage during this test because there are circuits that are supposed to be hot all the time, for example, the clock and the computer memory. You SHOULD read supply when the "ground/return" is open. When you measure across an open, you should read the full supply voltage.
The reason the voltage dropped in step 1.5 is that you finally removed power from the circuit.
Sorry, but your diagnostic method doesn't do anything to lead to the diagnosis of a faulty crank sensor or connection.
Glad it's working anyway.
Steve
