Hello. I hope someone can help. I have a 1999 Bonneville 3.8L vin 1 with 110,000 mi and i had some trouble with it starting. It sounded like a low battery because it cranked very slow. It did that for a couple days then it stopped cranking. I could here some relays click once when I tried to start it but nothing else. All lights and dash warnings are normal and the security light goes out after a few seconds. The lights do not dim when I try to start it. I replaced the battery with a brand new one and I charged it to full after purchase. All connections are cleaned and tight. Any ideas?

check and clean the other sides of those big cables, grounds and power to the starter.

if thats not it then your starter may be bad. check the voltage on the big wire while some one else hits the key should stay up not go to zero. if it stays up its probably your starter.

Thank you. I have to go buy a voltmeter and check that. I have cleaned all connections.