I have a 2008 Pontiac G5. The battery is about 7 months old and I had it tested and it is perfectly fine. Connections to the battery seem solid and clean. However, intermittently when I try to start the car, it's completely dead. No noise when turning the key, no interior lights light up, and I can't remove the key. Behavior of a completely dead battery. If I leave the key in, open the door, and close the door again, within a few minutes, the radio will light up. I can then start the car and all is fine until the next time this happens.
Other items of note when this occurs are that I've noticed that when the radio does come back on, the time is reset and it's switched back to AUX; like I just reinstalled a battery. I don't know if this happens each time. This is my daughter's car and I just noticed this. Also, upon the first start after this happens, sometimes the gauges won't go "true" immediately. I noticed the gas gauge wiggled at empty for a good 30 seconds until it finally shot up to the proper level. This does not occur every time. And sometimes once it does start, I've noticed a clicking (like something switching) under the hood in front of the steering wheel or sometimes it seems like the CD changer is trying to do something. Again, this does not happen each time.
All of those things in the last paragraph ONLY happen after I start it after it's been dead. And each thing is also occasionally. Most days, it starts just fine and there is nothing wrong with how anything operates. I'm a little stuck on what this could be and I cannot get any of this to happen reliably. It's completely random behavior.
