1999 Chrysler Concorde Own 2 7l Engine Battery Light Went On Recently Voltage

I own a 1999 Chrysler Concorde with a 2.7L engine. My battery light went on recently and the voltage at the jumper terminal is 10.4VDC with the engine running and goes back up to 12VDC. Was told it should be 13VDC and to change the alternator. So I replaced the alternator and found no change in voltage at the terminal. So I checked the voltage at the alternator and saw 30VDC. Now I am completely stumped as to what the problem is. I also would like to get access to the wiring schematic and to identify what components there are in the charging system and there function.
Thanks,
Richard
rczirpoli@hotmail.com