Does anyone know what this little condenser is for? My 83 GS came with AC, but now has an after market system. It was disconnected, couldn't even find where it was supposed to be connected to the harness. Single pole connection. Near the firewall, just next to the rear engine hoisting, top of engine.

 

That helps remove "noise" from the electrical system. Has nothing to do with the AC. One use is to improve the radio sound quality. In older cars, you could her a buzzing over the radio.

 

Is this maybe for the original Alternator, mine is a Mitsubishi and I think at least the second one on the car? I don't see a single pole hook up for it.

 

That should have about a 3" pigtail with a male bullet connector coming out of it. Wire is black possibly with a yellow tracer. Look for this color wire with a female bullet connector with a clear insulating sleeve somewhere in the vicinity.
Though your pic is not really clear,i don't see the above described wire/connector coming out of condenser. Likely got accidentally broken off/ripped out. Not really a big deal,you could find another on a scrapped engine or a car in junkyard,personally i wouldn't be too concerned about it.