I noticed yesterday that my battery gauge was running low in my 00 Z28, Car starts up just fine and the lights don't dim when I use other accessories so I'm kind of doubting it's the battery..Did a alternator check and that checked out fine as well. My gauge is at 9-10 which is at the beginning of the "red" stage and my check gages light came on, Beginning to think it may be my serpentine belt..only because my car starts up fine..sometimes there is some clicking while I am starting the car but nothing dramatic

 

Verify the voltage reading at the battery with a reliable meter. If still low, your alt is not charging and you are on borrowed time. When the battery gets low enough, it will not start your engine.

 

I've had it tested at two diff garages and pulled the positive cable off while car running and the alternator came back fine.

Think it could be serpentine belt?? Cause I know when I had it at garage about 2 months ago they had mentioned my belt was starting to take a crap and tear