I have a 99 z71 Silverado that the battery won’t start back up sometimes when the cars off and the light switch is off the stereo and running light will stay on, I can put my little jump box on it and it will fire right up no problem I’ve put a new battery on it and it still does the same thing. Is there a list of the fuses that tells you which ones are supposed to be constant and which ones are switched

 

Before even trying to chase down fuses, I’d first Disconnect the battery and clean the cable lugs if needed, then make sure the bolts are tight.

The cable sleeve at the terminal should be removable for thorough cleaning.

If the bolts are worn, replace them with 3/8” x 1-1/4” hex bolts with a nut threaded on. Snug down the bolt then the nut for a solid battery connection. The cable sleeve needs to be removed for using hex bolts but you can apply spray paint to the terminals to protect them.

The battery terminals on these trucks are notorious for loosening up and allowing corrosion build up, affecting battery connections which can cause control modules to glitch in several ways.

Second check is verifying the ignition switch is in the full off position as opposed to being caught in a “nearly off” position. A typically reliable test is to gently try turning the key past the off position.

I can’t recall when the accessory position was moved to forward of the off position, so expect 1 of 2 outcomes:

1) It’ll go into accessory and you will then need to cycle it back to the off position.

2) If it’s worn, you may feel movement or hear clicking of the key/switch as you rotate it back. If it does move/click, remove the lock cylinder to inspect for which components are worn.