I hope i am in the right area fro this.....Went out to get into my 2006 hhr heard a low tone coming from around the hood latch area, like an alarm tone, After i turned the key to start car. Car did not start, radio came on a/c fan came on. the only thing i have done is disconnect the battery and check the voltage which was 11.7. had my son try to crank it drop to 11.5. this is a my first hhr and haven't a clue where to start looking at this problem. Any help is appreciated

problem solved.

 

I don't know about your noise, but that battery is dead.

 

Yep. Should be 12.7 volts or higher after leaving it sit for 10 or more minutes.

 

Is there any chance you left something charging in the car like a cell phone, or left the headlights on, or a door ajar that left the interior light on?

Battery is either dead and needs replacement, and/or the charging system is not keeping the battery charged, or the battery needs charging.

You can try charging the battery, then check the voltage while it is running. When running the voltage should be 14+ volts indicating that the charging system (alternator) is working. If the voltage is that 14+ volts when running, but the voltage with the engine not running drops down below that 12.5-12.7V after it sits for a while, then the battery is toast. If you can take the battery into a auto parts store such as Autozone etc., they can load test the battery to see how much life it has in it.

Any idea how old the battery is? In hot temperature areas like Texas, getting 5 years out a battery means you are doing good.

 

Since the 1st post was edited to say "problem solved" (and they didn't explain ), I'll lay odds that they won't be back.
Posting useful help is probably a waste of time now.