my car electrical problem.

Background: My 16 year old daughter was gifted a car that has an electrical charging issue. The issue: It doesn't charge the battery. I did all the obvious stuff and replaced the alternator and battery and checked all the cables and connections.

I started digging around.  There isn't a lot of info online about this car's electrical system, but I did find this about one of the mystery wires that run from the alternator back to the firewall:

The "I' circuit (light green/red wire) turns the voltage regulator on when the ignition switch is in the run position.  This circuit turns the alternator warning lamp on if there is a problem in the charging system or associated wiring. 

I decided to check the voltage in this circuit to see what was going through this wire.  Turns out nothing was coming out of this circuit.  From what I could gather, voltage was supposed to be coming from some computer chip under the dash to the alternator telling the voltage regulator inside the alternator to kick on.  It wasn't, and this was likely my problem.  Probably a random electronic control module under the dash was bad.

Because this was a free car and I didn't want to put a lot more time or much money into it, I figured why not artificially supply voltage to the wire.  I mean, what could go wrong?  So I added a jumper wire from the power distribution box to the wire.  Presto!  This fixed the problem.  It's probably not AAA approved, but the charging system is now fully functional.