The fuse link is not at all dependable and is a high current "last ditch." Here is a marvelous story to illustrate that:
In the early 70's two girls in a Datsun "a holed" my nice 70 440-6 RR. During that time "I got to" drive a POS loaner, a Valiant more door slant. One morning at NAS Miramar, I was to get "off duty" at the RADAR shop, and it was (believe it or not) a fairly cold day, likely near freezing at about 6:30AM. I had started "the loaner" and went into the shop. The leading Chief came in, and he could do an EXACT impression of "Columbo."
Chief Waddell came in, looked at me, "knitted" his eyebrows like Columbo, and says "Mxxxxxxx, I just have one question? Is your car supposed to be SMOKING and making SQUEALING noises?"
So I go out there and shut it off THE ALTERNATOR HAD STOPPED. Bear in mind NAS Miramar, N of San Diego, is 20 miles from McCune Chrysler Plymouth, the POS hacks who were supposed to be fixing my RR. So I got a rag and loosened the belt to see "what."
IT TURNED OUT THAT WHAT was actually wrong, is that one of the diodes had FALLEN OUT of the heat sink INTO the INSIDE of the alternator and STOPPED it rotating, sorta like a wheel chock.
WHEN I WIGGLED THE PULLEY with my rag, I got to sit there AND WATCH the entire underhood harness turn to a melted, welded, smoking, stinking mess, emitting LOTS of smoke, AND THEN AFTER ALL THAT the FUSE LINK BLEW.
I went in and called the dealer, and told them, "your loaner burned up the underhood harness, send out another loaner car and a tow truck. Hours later, here comes the wetback with a beat up pickup full of old batteries and broken down booster cables. I went outside and he looks up and me and says "he man, it's all burned up!!"
