2005 GMC Sierra question

Hello All, I have a 2005 Crew Cab GMC Sierra Z-71. I love the truck, but have a major issue with something the local service department and GM says is
normal. When I leave the truck parked for a long period of time (so far 20 days and 21 days) the battery dies. I travel with the Air Force frequently, so this is becoming a real aggravation. The dealer says it is normal for the battery to drain in about 2 weeks due to the 7 onboard computers. My 1997 Camaro SS sits for longer than that sometimes and starts nicely. I had a 2002 Silverado Ext Cab Z-71 and left it for sixty days once with no problems. The only difference I can see is the GMC has OnStar, and the Bowtie didn't! I know some things had to be changed from the 2002 to the 2005 models, but enough to cause this?!! Anyone have opinions or similar experiences? The dealer changed the battery both times I took it in! I did notice there were a few new cars on the showroom floor with the hood up, and a battery charger connected! Thank you in advance for any replies.
Jerry
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According to the On-Star literature, it should power itself down after 48 hours. When I had a similar problem with 2002 Silverado, I traced the 'leak' to the lightbulb under the hood. It has a simple weight switch, that is supposed to come on when the hood is lifted, and turn off when the hood is put down. Mine was staying on when the hood was down.
To see where your leak is, use an amp meter, and test across each fuse link (without the fuse in), and see what is drawing current that shouldn't be when the ignition is off.
John
JP wrote:

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John




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no your battery should not die after only 20 days of non-use. I don't think the pickups have that many computers either, but anyway if you have a good battery you should be ok. I would think you have a battery drain somewhere?
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Elbert Clarke
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Hey Guys, Thanks for the responses. The last time I took it to the GMC/Pontiac dealer, they ran a parasitic drain test, and found nothing wrong. All computers went to "sleep" as designed, and according to the service manager, there was no abnormal battery drain during their test. This time they changed out the battery (again). This is the second battery. I am just going to have to do what John suggested and check every circuit myself! The "that is normal for the battery to die in about 2 weeks" answer seemed wrong to me. Once again, thanks to all.
Jerry

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You could try one of those solar power trickle chargers or something similar for the time being just as a temporary solution......but something doesn't sound right, I don't think I'd be as nice about it as you are, and you certainly shouldn't have to probe circuits on a new vehicle under warranty. R

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Jerry,
if the guys the dealership are right then a Cadillac would not make it a week without starting or the battery would be dead.
The Cadillacs have (in recent times) been the king of electrical devices and were the first to have so called BCM computers along with the ECM. Now in the present most all cars have an increase electrical load not only when driving but also when the engine is not running. I would have to say that any car should go a couple of weeks without the engine running and the car should start. If the alternator is working then its either the battery or a parasitic drain on the battery (my view). Hats causing the problem. I don't think its "normal" for this to happen as you described. If it happens again and you are under warranty I would want the dealership to install a heavy duty battery.
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Elbert Clarke
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Thank you all. I guess have been a bit too nice to the service department about this one! I read, considered, and appreciate all of y'all's inputs.
Jerry

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JP,
Just returned from a 3 week trip and was checking news groups when I came across your post. I have a 2005 Silverado and it sat out here in Texas for the whole time. I just went out and it started up with no problem. I don't have onstar, but everything else. Just thought you'd like to know.
Good luck, Karl
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Thanks Karl, I'll use your story the next time the thing dies! Take care.
Jerry

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