What Nanket said & if good in that large cable system then next time it goes dead see if you have fire at the alt "batt" stud & you might seperate/check/clean the bulkhead and check the ammeter terminals in that path. For it to be completely dead there would need to be an open between the batt positive post to/thru the bulkhead & to/thru the ammeter to the "welded splice". Bulkhead/ammeter are culprits & with it going completely open/dead you'll easily see it (poor/loose connection/terminal) with some checking