Just replaced the battery and starter and had the alternator checked. Alternator was good. It won’t start or turn over but lights and radio and ac comes on.
First check the in line fusible links. Then check the Crank Relay located in the underhood junction block. Use the provided wiring diagram to help with your auto repair.
Starting System Wiring Diagram – 2001 Chevy Impala
(best viewed in Google Chrome browser)
2001-chevy-impala-starting-circuit-1-of-1