Truck Repair: El Camino question..., chiltons manual, generator light

Question
Mr. Bond:
I've got a 1979 Chevrolet El Camino with a 350 engine (4 barrel carb).  It's in pretty good shape, and the motor runs well.  But whenever I crank and run it, the GENERATOR light stays on.  I took the generator (alternator) off and took it to an AutoZone.  They tested it, and said it was fine...so I know it's not a bad alternator.  I'd like to start using the truck, but if the alternator is not actually re-charging the battery, it'd be a problem.
Can you give me any suggestions as to what could be wrong?  I thought I'd trace the wiring from the alternator to the battery and see if I could locate any shorts, etc....can you suggest anything else?
Any advice greatly appreciated.
Warm regards,
David Gardner

Answer
Well, what I would do is check your battery, have that tested also. If this checks out, maybe you have a false reading from the lite, maybe a short/loose wire? You can also rent a Chiltons Manual for this vehicle, it should have a picture of the electrical system. I would start there. Another thing start the vehicle turn on all your accessorys, lites, radio ect if the vehicle dies after a short time then your alternator is bad. If it doesnt start, then its your battery. But those 2 things are a general idea, to try.. Ty