I am attempting to replace my old Paris Rhone alternator with a new API Marine alternator. The Paris Rhone had 3 wires, Red (+), Black (-), and a purple wire with a resistor on it that went to a terminal labeled 61 (which looks like it's just 12V from the key that also goes to the coil from the wiring diagram on the volvo website). The new API alternator has a screw terminals that are red, black, and one that's white that has a tag on it that says "AC TAP-Tachometer caution hot lead." Is the purple wire no longer needed with this new alternator? Should anything be hooked up to the "AC TAP"? Also, the new alternator has what seems to be a grounding screw on it's case, does something need to be connected to that terminal on the case?