2002 silverado. Truck starts after several silent attempts, auto headlights didn't work but now do, auto door locks don't work, radio locks up due to power failure off and on(4 times), interior lights no longer work manually, etc. What's wrong?

Clean your battery terminals and have your battery tested.

Remove and fully charge, or replace, your battery. Most auto parts stores will test and charge batteries for free. If you get a new battery, have it charged prior to installation. Clean battery terminals and cable connections. Afterwards, check the alternator--regulated battery voltage should be 14 to 15 volts, while the engine is running.

clean your battery terminals and have your battery tested.

Battery not problem-checked out good. Still have same problems

. Test all under hood and under dash fuses with a test light or multimeter. The results may lead you to an intermittent problem with the ignition switch.

. Check/replace the starter relay, likely located in the under hood fuse/relay box. Try swapping a similar relay in the box, provided they are the same part no.

. Check body control module.

How did they test the battery?