I have 2007 Impala. We crunk it one morning and it just cut off. Then it wouldn't crank and none of the lights inside or radio display would come on. Starter is good battery is good and fuses look good. I have also changed the electrical ignition switch. Help?
If no interior lights work but the battery is charged then you may have a problem with the electrical connections going to the 2 battery terminals (also known as posts). The connectors may have come loose or there may be corrosion preventing electrical contact. The first thing I would to is make sure the terminals and connectors are clean and tight.
If that is not the problem then you have an electrical problem somewhere else going to or from the battery, maybe a bad cable, or loose connection somewhere else. Finding that is a matter of tracing those connections, testing as you go.