Hey all, the other day I let my friend's wife borrow my truck to pick up some dirt, and while she was driving down the road the truck started smoking from under the hood. She pulled over and long story short, when I got the truck back to my house and got a good look under the hood, the positive cable from the starter to the battery was fried, as well as the negative from the terminal to the body. After doing some research it seems like I'm missing a ground-shouldn't I have a negative to the engine block and a negative to the body?
The cable from the positive to the fuse box looks OK, and the other wires leading to the starter seem OK too so I'll start with replacing the positive and negatives, and probably making some new grounds. Any suggestions or ideas on what might have caused this in the first place?