is the alternator grounded with a black wire. What do the connections look like? on 1993 Nissan Pickup (D21)

I put in new battery and it slowly drains down. I don't see a spark when attaching the terminals so I don't think there is a drain going on. I looked for loose wires and found a disconnected black wire near the alternator.

Asked by for the 1993 Nissan Pickup (D21)