I was going to work this morning and i started to smell some plastic burning but it quickly went away. After that i checked the fuse box and where the alt fuse is was all melted! The fuse for the alt wasnt event broken everything else around it melted, the brake light and battery lights are on! anyone know what happen. its a 1994 Totota Pickup 4x4

 

My guess....a loose connection generating heat via resistance possibly.

 

What he said kinda

A loose connection in any electrical circuit will get real hot in very little time

Was the connection loose when you removed it

 

they were tight on there as far as i know i havent messed with the wiring that much untill now. i know for the longest time when i turned my blinkers on or when i went accelerated and slowed down everything would go hyewire. i just rebuilt my engine maybe something is loose somewhere

 

This sort of thing happened to my truck a few years back. Check the main alt charge wire for any melted spots. https://www.yotatech.com/forums/f131/lights-out-266855/

 

so i think i found the problem. while back i bought a new alternator from O,Reillys and turns out that they sold me the wrong alternator! It was pushing 70amps instead of 60amps and it fried some of my electrical componiates! Im pretty pissed at O'reillys right now! It was an alternator for an automatic in instead of a manual.

 

the alternator on my 22re puts out 140 amps max, and it hasn't fried anything.

 

I guess it was the type of alternator because it was recently bought and it just fried yesterday

 

I tend to think it was corrosion and under sized wires. I have a 4ga wire from the alternator to the battery just to help out. The wires are pretty darn small. You would think using a larger gauge of wire would kill them.

 

Concur with rworegon.

Higher amp alternator will not cause it. However an alternator with shorts (Auto-parts store sell bad alternators once in while, correct?) could.
Disconnect battery cables.
Disconnect "B" wire from aternator screw post. Measure resistance from screw post to ground. try to rotate alternator if possible. resistance should read in meg-ohms. Lower than that means shorted winding or rectifier.

Cheers!