The stock alt is tothe optima in the front .the 200alt is connected to a kinetic which is in the back ...the kinetics ground is the same ground used for the amp i have. If tat matters and the alt works it was my primary before i got the stock from the van and i checked both alts using the optima and they both seem to charge fine. Before iput the other alt , the 200amp alt handled the whole truck solo and the lights flicker and volt drops to a low 12 mid 11s volts and yes ive done the big three