alternator plug on 87 and 89

[cmahometech]

I am swapping in an engine from an '89 blazer(with the serpentine belts) into an '87. The wiring harness for the '87 alternator has two wires going into it (a pink with black stripe and a brown). The '89 alternator only had one wire (pink). What do these wires control and what will the 87 computer want to see? Can I plug both wires into the alternator that was only using one before? I cannot change alternators because the older one had the v-belts and the newer is serpentine. /forums/images/graemlins/confused.gif