Not sure how you have approached this, so let's cover it from the start.
What voltage was the battery showing, car not running?
What voltage was showing at the battery with the car running?
The ammeter is just about worthless for troubleshooting much of anything.
Gen light still on?
Voltage not over 12 volts at the battery with the car running means you are getting no charge from the alternator. Should be in the range of 13.5 to 14.5 volts.
Larry
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