Hi, If you are talking about the anti theft device that locks the radio, you might have to go to the dealership to have it unlocked. That's what I did when the radio on my 2000 Sunfire stopped working after the alternator was replaced. It cost me $20.
How is the ignition key switch replaced on the 2000 Pontiac Sunfire? And after replacing the switch would I have to have it Towed to the Pontiac Dealer in order to have the car key programed to the Computer?
Generally, as you face the car from the front, the alternator should be on the left side of the engine where the belt is. The belt drives the alternator. The alt in my '96 is right up top. You'll see an electrical connector going to it.
Connect a voltmeter across the battery terminals without engine running reading should be around 12.8 With engine running reading should be 13.8-14.2 if you are getting these numbers alternator is charging battery