> the voltage across the battery should be about 13.2 volts when the
> engine is shut off. It should be about 15 volts when the engine is
> running. you definitely have some sort of problem. Maybe start by
> disconnecting the battery, charging it over night and check the
> voltages the next day. I think sometimes if the battery is fully
> discharged the alternator will not even try.
He already cleaned the terminals and charged the battery. But, I agree,
now he needs to do it again before proceeding.
Whatever the OP does, he should work logically and systematically.
Dont start throwing new parts at it. Test, diagnose.
If he has one of those GM original battery cables that has several positive
leads going into the one side connector, he needs to be sure he has taken
that apart and checked/cleaned the INSIDE of that terminal assembly. That
is a common place for bad connections to occur.
The supplier where he bought the alternator should check it out for him for
free. Check it, at any rate.
Go step by step.