I have a 2009 Cobalt with only 34,000 miles. Its a basic model - no power windows/lock/seats/cruise/remote start or anything else "fancy". Had a new battery put in in Feb 2016 because it wouldnt start after it was parked for 15 minutes. All was fine til 3 weeks ago when it wouldnt start again. Had it jump started, it was fine for a week. Then wouldnt start again, had it jumped again and it was okay for a few days. Last Wed it wouldnt start, I left it parked til Fri morning and it started on its own. Sometimes when it wont start, the radio, dash and other assesories work. Sometimes it wont start and nothing at all comes on. I've had it checked by 2 repair shops and a Chevy dealer, they all say its not the alternator and I was told it was a bad battery. Got a new battery and it wouldnt start again the next day. I cant drive anywhere because once its parked I cant be sure it will start again. Meanwhile I have to take the bus to work, cant go anywhere and have used up my maximum number of AAA service calls. Am it my wits end with this thing and dont know why no one can seem to find the problem. Not sure what else to do than take it back to the dealer and have them look at it again. Any one have any guesses??

 

Neutral safety switch was my problem

 

If it's a manual tranmission you need to make sure the clutch engagement switch is working on the pedal. I had a similar problem where the clutch pedal switch wasn't being engaged and obviously the car won't start if it doesn't think the clutch is engaged.

 

Sorry, forgot to mention thats its automatic transmission.

 

A problem with the neutral safety switch wouldnt cause the battery to drain and the dash instruments to not display, would it? Cant figure out why its not at least getting power to everything, even if it wont start.

 

If it's losing power and your instruments don't work then you obviously have something in the car that's always pulling power.

I'm not good with finding that crap

 

Does this mean you didn't need to jump it to get it started? When it doesn't want to start, is there voltage in the battery?

If there's voltage and it won't start, it's likely not the battery. More likely a loose or breaking cable somewhere that's causing intermittent problems for you. If your battery is dead each time, then yes you have a significant power draw that you'd need to find with a good multimeter.

 

It usually does need to be jumped to start it. But last Wed night it wouldnt start after being parked for 15 minutes at a store. I left it til Fri morning and it started on its own without a jump. Doesnt seem to matter how long its parked, anywhere from 15 minutes to several days and may be dead the next time I try. But then sometimes starts again on its own and sometimes doesnt. After its jumped it sometimes starts fine for a few days. Its all just so random. Before AAA jumped it the last time I think they said the battery "tested good", but it still needed to be jumped to get it to start.
Just called the dealer. I'm going take it in again on Thurs and sounds like they are going to focus on it being a parasitic draw problem. Thanks to everyone here for the info

 

How about a loose ground cable? I would look into that as well.

 

I'm assuming they're jumping from the post under the hood? Every time it's jumped it works? If yes to both, it's the battery cable.

 

Yes to both. Thanks for the info, will add it to my list

 

Is this a good battery or a Walmart 50 dollar battery. Sounds to be something is pulling power. An expensive good battery will help bandaid the situation. On hook anything that's been put in aftermarket