[John Rogers]

Do you have one of the electrical kill switches installed? If so it can fail with notice. What is the voltage at the lug with the large wire from the battery when you try to crank it? Seems like enough voltage is at the yellow or ignition switch wire so have someone try to crank it while you measure voltage at the lug. You can also check the large wire from the battery for resistance and I forget what the spec is but they do degrade over time no matter what some say. It should be battery voltage.