I have a 08 Silverado 5.3L with 57,000 miles. For the past month I have noticed a few things starting to mess up. The first time anything happened I was driving when the door locks unlocked and locked within a second, and I also noticed the air bag light started flashing. When I got home and turned off the truck, it killed everything. The key fob wouldn't work at all, when I turned the key it acted like there wasn't a battery connected. After letting it sit for 5 minutes everything came back, and my clock was reset to 12:00.
Ever since that day, I have noticed my radio fading in and out, my headlights dim and flicker when I press the brake pedal, and my cruise control will turn itself off while driving for no reason at all. Not to mention it sill likes to reset the clock after turning the truck off. Any suggestions? Battery clamps are snug and free from corrosion.

 

I grandpa's truck did the same thing
Replaced battery all is good now