1997 Buick Century wont hold charge

You need to be more specific than, "a wire that wasnt getting power". You only need two wires to make that generator work. If the "Battery" light turns on when you turn the ignition switch on, that circuit is okay. The second one is the fat wire bolted to the output terminal stud on the back of the generator. That one must have exactly the same as battery voltage, with the engine off and with it running.

The first thing to do is measure battery voltage with the engine off, then with it running. With the engine off, it should be 12.6 volts. If it's low but at least 12.2 volts, charge it at a slow rate for an hour, then do the two tests.