help! electric shock

hi everyone, its me again.i just found out that my car has an electric shock. it is the second black cable that is on the circuit panel over the battery.but it leads inside the car, and connected inside a black box that is behind the head lights control switchs.inside the black box their are 4 red wires,and one with lower resistance is connected in a railler

i would like to know the purpose and where the 3 other are leading, because 2 to of them are the cause of my problem

so please help me out.

vegetu