Working on doing Big 3 upgrade. I've found the wire from battery to chassis. I've found another thin ground running from above the alternator to the chassis (I assume engine block to chassis). I'm unable to locate where the ground from alternator is? There is a thick gauge wire coming from under the plastic cap on the alternator, but I haven't traced it yet, and assume it is actually the positive out?? I'm no mechanic, and this is the first time I've gone this big with a stereo system that I've considered doing all of this...Sorry for the noob questions!