Good Alternator Won't Charge - Please help

[CSJ3 notchback]

I have a 1990 Notchback 5.0, I just put a new Interstate Battery in it and have been running a PA Performance 3g alternator in it for about 2 years with no problems til now. I left it out in the cold for a weekend and when I started it up the volts were low. The battery has been checked at 2 different places and is good, the alternator checks out good and all the large battery/ground/alternator wires have been replaced in the last 2 years also. Connections are clean, battery light stays on while running and I checked to see if it would go out when I unplugged the wire from the alternator and it did so I assume that circuit is fine. Something Is there another "exciter" wire I should be checking??? Any help would be greatly appreciated, I need to get it fixed asap.

[bourbon]

dont know anything about the alternator you have. have you hooked up a voltmeter to the car so you can see where its at while running (charging)? you should be up in the 14 volt range.

when you say battery light comes on do you mean the ALT light? sorry but i dont drive my mustang much anymore so if there is a battery light you will have to forgive me. if the ALT light comes on it means your not charging the battery and your alt. is to blame. did you ever think that maybe your old battery may have been bad due to a bad alternator? is your belt slipping around the alt.?

also, dont be connecting or disconnecting the alternator wires while the car is running it could affect the computer or other circuits. EFI cars are sensitive thats why i have a love hate relationship with mine.

oh and if your car has a factory voltmeter dont look at it cause im sure its wrong. use a digital voltmeter.

[CSJ3 notchback]

I actually figured it out a couple weekends ago, it eneded up being the power wire to the regulator side, must have been cut or shorting somewhere so i ran a new wire and disconnected the old, works perfect now. Thanks for the reply though.