I know that just like a doctor's diagnosis, figuring out the source of an automotive problem involves picking away at the obvious. But its seems like with this example, they were into some pretty serious repairs, swapping out alternators and such. Perhaps a glance at the car's structure might have been in order? Seems like this is a classic example of every anti-best practice, from manufacture on the assembly floor to service in the shop.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.