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Gary, Chevy Technician
Category: Chevy
Satisfied Customers: 16896
Experience:  15 years GM master tech
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Chevrolet 07 avalanche LTZ: My 2007 Avalanche LTZ appears to

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My 2007 Avalanche LTZ appears to have something intermittently draining the battery while the vehicle is off. It will do fine for several weeks/months then overnight the battery will be drained.

In May the Chevy dealership in Brownsville, Tx worked on it to resolve this issue (had to be towed there). They decided it was an an ignition 1 relay shorting out. So they fixed that and replaced the battery.

Has been fine until a few days ago. Truck had not been used for a couple of days and was totally without power. The remote unlock would not work or even the inside door lock opener.

Towed again to Brownsville. Haven't heard anything for two days.

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boy intermittent battery drains are tough to nail down

so this will act up when ever it feels like it ?

Customer: replied 3 years ago.
Yes. But not an every day drain or even every month. Seems to be related to something in the truck which could activate by itself for some unknown reason. The truck is in great shape - still only 60,000 miles on it and has been maintenanced. With me being the only driver

99% of these intermittent draws are caused by the radio or the BCM on these trucks

either one of them will intermittently not go to sleep so to say and when either one will not go to sleep it will draw it down over night

they need to keep retesting it and try to catch the draw which will be tough but once they do they can tell which is not powering down

if they can NOT catch it acting up and the battery and alternator test out fine unplug the radio and see if it will act up again if it doesn't act up again its the radio if it still does this the odds are the BCM is the draw

most other draws we see are drawing all the time where when its doing that you can nail it down very quick but with it intermittent its usually one of the 2 not going to sleep



Customer: replied 3 years ago.
Then you do not think that the security system or the (not used) On Star could do it as well ?

ive never seen a security system pull down a battery unless its an add on aftermarket one installed

as for the on star I have never seen one yet draw down a battery

I mean at this point it can be any module so to say drawing it down intermittently but the 2 most I have seen where radios or BCM's

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Customer: replied 3 years ago.
What is a BCM and what action would need to be taken if its that ?

BCM=body control module

the BCM would need to be replaced and the new BCM reprogramed with your trucks VIN number