Where can I get a wiring diagram for the alternator circuit?

Any charging system trouble codes? With engine running, take voltage reading at alternator bat terminal. Is it the same as across the battery posts? If the reading at the alternator is higher, then there is a problem with wiring circuit from alternator to battery.
There may be a battery temp sensor, that you need to check?
I don't have a wiring diagram for your charging system, so I won't be much help.
With newer vehicles, The charging system is usually computer controlled.
If problem with wiring circuit, somewhere, replacing the components won't fix it.

Ford Crown Victoria Alternator Wiring Diagrams

If you go to Google images and search for alero charging circuit you should find a wiring diagram photo.

Alternator F terminal circuit. Check your plug-in in the Alternator case. The field wire is not connecting. You could have a bad supply wire from the Ignition switch or a Relay.

Check with Autozone.com and register your vehicle for free wiring diagrams and fusebox layouts. Some GM vehicles use Relays or fuses in the charging circuit.

You have a broken wire, get a wireing diagram off line ($15) I believe it's the field wire, I hate guessing but I don't have the diagram.

http://wareznuke.com/apps/3872/all-1979-2007-vehicle-wiring-diagrams-v42-rapidshare-warez

Most likely...seems like you have a handle on it. There may be wiring diagrams available, for example Chiltons manuals...To my knowledge there exists no "internal" wiring diagrams for alternators of any make.
Good Luck

just put a one wire alt. on it.or test each wire.

Yes it is the wire that comes from the alternator/battery lite in the dash.

Possibly a fusible link somewhere in the circuit has burned through and disconnected the circuit.A wiring diagram would be needed to look for the location of any fusible links Ohms check the wires involved in the alternator charging circuit to verify continuity.