This problem gave me a real headache the volts drop from 14s to high 11s as soon as I apply the brakes,opened the taillights and checked all the bulbs all of them were correct and cleaned the connector but no use,I remember one time I removed the black wire from the alt pig tail and the problem gone then I searched for alt wiring diagram and did put an idiot light and it didnt solve anything winter is coming and I want to fix this ASAP

 

I would check for a ground issue for the tail lights or volt gauge. Does your gauge drop or flicker when you turn on the parking lights or head lights? Are you reading the factory volt gauge or aftermarket gauge? Bad grounds usually cause this problem.

 

Factory volt gauge and all the lights fade away when the volt drop,where can I start checking for grounds? I even checked the switch above the brake and its fine there is something causing this short when applying the brakes

 

I've found the two red lead wires that go through the firewal have been cutted and ghetto attached by a thinner single wire going to the battery I will put two inline fuse on them and both will go to the battery and see from there

 

I connected the two lead wires from firewall to the battery the volt isnt dropping like before but it stills drop I think what left is the crank pulley