Alternator went to crap a few days ago. Replaced it with a napa (yeah i know) reman unit. I pluged it in and all was well for a week or so. Then today the alternator fell off its mount since I failed to install the nut on the bottom pivot bolt (oops). Bolted the alt back up, and had abslolutely zero power with ignition switch on, not even dash lights etc.... Since I conveniently broke down near a car parts store they tested the alt and it kept tripping the breaker on there machine. They had a new unit but it was bad as well since it triped the breaker too! So, my question is, if the alternator is crap, will it prevent the truck from getting any power at all with the key on? Is there some sort of inline fuse? Im guessing the regulator is internal, but a marlin post said its external. I think I need to just do the gm alternator swap