driving home 65 mph or so volt gauge started bouncing to neg side, same time engine would misfire.Next day went to start it battery was dead,dead put charger on it to start turned key on to start it volt gauge pegged to neg side,then i noticed it let the smoke out of fusible link,not good melted engine harness plug and bulkhead side where fusible link goes. any ideas???

with a reasonably charged battery start by taking off a cable at night from its post & touching it back to the post & see if there is a spark (with doors shut/everything off there should not be any draw unless you have a clock or a lighted stereo faceplate or similar). then we can check if the blue wire field circuit is grounded including the alt field terminals. is the reg an OE type with the wire would resistors on the bottom side?

The bulkhead connections are a weak link in the electrical system- dirty, loose, or corroded connections will contribute to high resistance, which leads to heat, which can contribute/lead to a meltdown as you described. If all other components check out fine and nothing failed, then that is a likely culprit. Also check the connections on the back of the amp gauge.

Your symptoms describe a dead short somewhere that lead to the fusible link doing what it was supposed to do. The question is, where is the root cause and how much damage id it do to the wiring before the link blew. If you are not familiar with electrical troubleshooting it maybe be time to find someone who is as the problem could be anywhere

took bat terminal off alt no more dead short so it seems it is in alt.noticed bat terminal was a little loose and somewhat crunchy.good old re man carquest junk not even two years old . thanks to all who replied

Check your underdash harness , when the alt goes dead short like that it's usually melts the main wire to the amp gauge , also check and make sure it wasn't the amp gauge that caused the short.

take the batt cables off of their posts and then keeping the positive cable you just removed from touching anything while it is dangling and with the black wire still off of the alt "batt" threaded stud like you did, see if the black wire has continuity to ground with your meter on ohms. with the black wire off of the alt batt stud, see if the stud itself has continuity to the nearby alt case (it should not)

bulk head connector not good, new one on the way,wire to volt gauge seems fine,gauge end is tight to gauge ,will have to clean plastic off and out of bulk end. what is the proper test for gauge

some one knew i was going to ask what the test was. thanks

Do the amp meter by pass. And the headlight relay.