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Hello, I have a 2009 G8 GT and my battery keeps going dead. I have replaced two of them in a four month span.

Door chimes and lights worked fine on Saturday when cleaning out and Monday morning everything was completely dead can't even remove key.

After researching here on the forum I see that OnStar can cause battery drain. Can I just unplug the module in the trunk or do I have to remove the OnStar battery as well, to stop the OnStar from draining my battery?

Thanks for your help.
 

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Yes, you can just unplug the Onstar box.

Be aware that you need to have the trunk open and ignition off until the system closes down. (about 5 mins) or the Onstar battery will activate and it's a one time use. (Not that you probably care about this battery)
 

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I can't see the Onstar box being the whole problem with this battery drain problem.
My box is still hooked up after all these years, my car sits for days un-started now that I'm retired, never has my battery gone dead.
The original battery was replaced 2 years ago due to old age.
 

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What brand(s) of battery are the replacements? Are these new or used batteries?
 

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I agree as it appears that it's been OK for years.

When did it start doing this? Anything changed around then?

I can't see the Onstar box being the whole problem with this battery drain problem.
My box is still hooked up after all these years, my car sits for days un-started now that I'm retired, never has my battery gone dead.
The original battery was replaced 2 years ago due to old age.
 

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Can almost guarantee the Onstar box is not draining the battery although stranger things have occurred. Ditched both the box and battery after the complimentary trial ended and never looked back. Any aftermarket electrical parts installed? Any other electrial issues before the battery trouble?
 

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Discussion Starter #9
The only thing I have added has been the aerpro radio kit and radio, however that was a while ago before any of these problems.

Also changed to factory AC compressor also a while ago.

I usually leave my keys in the ignition, don't know if that makes difference or not.

Could just be in my head, but it seems to drain if I go back to vehicle and open door or trunk after initial cutoff, keys still in ignition.
 

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To correctly find a drain you will need to hook up a 10 amp ammeter usually on most DVOM, remove one batt cable, install ammeter between cable removed and to batt post where cable was, let modules power down 20-30 minutes, if 0.05 amps or above, you then pull fuse to suspected component then let modules power down and see if lower than 0.05 amps to find culprit. Welcome to my World !
 

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...I usually leave my keys in the ignition, don't know if that makes difference or not.Could just be in my head, but it seems to drain if I go back to vehicle and open door or trunk after initial cutoff, keys still in ignition.
Are the keys left in the ignition in the on/run or accessory position? If on/run, about how long before turning the ignition to off? Is the procedure repeated multiple times before starting the vehicle?
 

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Would almost be inclined to listen and observe while sitting inside the car with everything powered off. Anything plugged into the on-board diagnostic port? Any gremlins or electrical related issues prior to both battery's being drained? Could be a long shot and perchance worth a gander, Pontiac G8 Forum
 

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It’s one of two things. Radio or amp is wired to full time 12 volts or the key is not back to the lock position. Most simple test in the world. Charge the battery. Take the key out and drop it in the cup holder. See if it starts in a few days. If it doesn’t, then the radio wiring needs to be checked
 

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Discussion Starter #15
Thanks for your help guys!!

I unplugged the OnStar stuff.

I checked the ground by the battery, the bolt looked good, but my amp was grounded there, so I moved it.

I reprogrammed my tune with the cortex, that seemed to reset the computers, so I will see how it works out.
 

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Typically, the exposed portion of the battery ground bolt is where the issue lies. The amplifier should have a separate chassis ground. Am not familiar with Duralast Gold batteries, but vowed to never buy another red-top (at the time) battery.
 
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