Got a photo?

6 prongs? It sounds like a regulator, except it's on the wrong side of the car. Although the 210 is a different beast. The regulator on the regular A12 sits on the Left side of the car (US Drivers side)

The only relays on the other side, might be an A14 regulator (as the alternator is on the other side), or the headlights relay, which doesn't have that many terminals.

With the engine running, put on your "high beams" and see if the noises change. But you'd be better to trace the wires.

If it's a non-nissan alternator (not lucas or bosch), then it may have a strange external regulator.

Post a photo, or draw us an approximate photo in paintshop.

Chris