Does anyone know what the small cable going from the negative battery terminal is?

[papertowel]

Im trying to figure out if some of the issues I have been having are related to a grounding or wire issue and I noticed that the small wire going from the negative battery terminal looks like its almost fried, the outer coating is completely stripped so its just the bare thin metal wire and it looks corroded in some spots but I have no idea where it goes ect.

 

[HotZ28]

Bingo, if you are having electrical issues with anything that depends on chassis ground. That wire needs to be replaced with a larger wire! Follow the wire to the chassis ground terminal & clean any contact surface before replacing with the new/larger wire.

 

[OB1]

I believe that is to the fusible link, It looks like a giant spade fuse