Stubs,
you make some damn good points, can have voltage, but a bad cell will not allow enough amps, my first choice is STILL switch the battery, AT LEAST, and only then can one eliminate the battery, still way too many places to look for a problem. A rat could have chewed through a hot wire somewhere, I doubt it but sht happens.......
Carl - take the battey out of your car,truck etc.. hook it up to the leads and see if flashers come on.....