I haven't updated this thread but here is whats happened so far.
Im gonna send this alternator back to the seller and while I was waiting I went ahead and ordered one from autozone.
I got the new alternator (still a remanufactured one) and installed it.
It's doing the same shit as the other alternator. 11.8v output from it.
But I discovered something after doing more tests with the voltmeter.
12.4v at car battery
12.4v at top of "T" connector. (also known as "Sense" connection)
0v at bottom of "T" connector. (also known as "Lamp" connection)
12.4v at alternator BAT terminal.
12.2v at battery
12.2v at top of "T" connector ("S" connection)
11.7v at bottom of "T" connector ("L" connection)
12.2 at alternator BAT terminal.
So in the swap guide I mentioned it says this:
"1. An "L" connection which goes to a "switched" 12V supply. By this I mean a 12V source that is active only when the ignition switch is in the ON position. I use the mnemonic "L" for "lamp", the alternator warning lamp (if used) is in series with this connection. This terminal also supplies the "excitation" current to the alternator field winding at engine turn on, allowing the alternator to begin producing voltage as the engine is ramping up to idle speed. Once the alternator rotor is turning fast enough, it generates it's own supply for the field winding and the current in the "L" connection stops flowing. The warning lamp (if used) goes out."
So when the key is on, the "L" connection gets 12 volts, which gets the alternator to charge.
My connection is only getting 11.7v. Could that be why it's not charging? I have the car battery on a charger right now in case it's not charged enough to supply the right voltage to this connection.
But everything else is getting 12.2v when the key is on... What's the first place I should look to find out why it isn't getting 12v?