H3 Mystery battery drain in 06 H3

[adventuredad]

Has anyone had trouble with a mystery battery drain? I’m looking at buying my first hummer and went to the dealer to check it out today. They had it at the Chevy dealer to get checked out because when it dat for several days the battery would be dead. After jumping it, it would run just fine and if they started each day it would be fine.
The test equipment estimates it would drain in 7-8 days of no use.

The previous owner put in an aftermarket stereo with a sub in the back. My guess is that there might be something wrong with that wiring but they are working on trying to find the issue.

Just thought it would be worth asking the group to see if anyone has dealt with a similar issue here. Thanks for the help.


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[alrock]

Always start with disconnecting aftermarket items - and with that stereo, that would be my first choice. But you could also be dealing with a worn out battery. Was their equipment testing a draw on the battery or the ability of the battery to hold a charge?

 

[3rdH3]

There were some posts years ago about the OnStar Module causing a drain. A search may come up with something. Good Luck.

 

[Traxx]

May be a combination of a weak battery and improperly installed amp for the sub. Many people run the +5 amp turn on to constant 12v instead of switched.

 

[adventuredad]

The equipment is testing the draw on the battery. They've replaced the battery already so it's not that. They still have it and are working on it but trying to do my own research.
Thanks

 

[adventuredad]

May be a combination of a weak battery and improperly installed amp for the sub. Many people run the +5 amp turn on to constant 12v instead of switched.

I didn't get a chance to dig through the wiring myself as they still have it but I'm guessing it's something along those lines.

 

[deserth3]

Also if you have a factory trailer hitch. The trailer connector wiring will chafe where it runs under the rear door.

 

[SlcHummer]

I agree about the aftermarket stereo and would think that it could be disconnected and then tested to see if any difference in the results. When I bought my H3 I was told the stock stereo was slowly draining the battery so an aftermarket stereo that I selected was installed free of charge and a backup camera included. I haven't had any consistent issues with starting my rig (knock on wood) but I also don't go 7-8 days without driving it. I did have one incident on a recent trip where it sat for 5 days and was dead when I tried to start it, so it's possible I have the same issue as you and the stereo replacement 4 years ago never actually fixed it lol.

I had a wireless OBDII reader that I left plugged into my rig the entire time that I hope contributed to this issue. I charged my battery and all has been good since. If in the future I go an extended time without my rig and have starting issues I'm guessing I'll find myself back here looking for answers, so please share your results lol.

 

[f5moab]

You can always find a drain by connecting an amp meter and pull the fuses one at a time till the drain disappears. If you don't have an amp meter that cannot read about 30 amps, you can use a digital volt meter and a shunt and read off the volt scale. Also use an actual GM schematic for what is on each fused circuit. The owner's manual may miss an item or two when describing what is on a fused circuit.

 

[adventuredad]

I agree about the aftermarket stereo and would think that it could be disconnected and then tested to see if any difference in the results. When I bought my H3 I was told the stock stereo was slowly draining the battery so an aftermarket stereo that I selected was installed free of charge and a backup camera included. I haven't had any consistent issues with starting my rig (knock on wood) but I also don't go 7-8 days without driving it. I did have one incident on a recent trip where it sat for 5 days and was dead when I tried to start it, so it's possible I have the same issue as you and the stereo replacement 4 years ago never actually fixed it lol.

I had a wireless OBDII reader that I left plugged into my rig the entire time that I hope contributed to this issue. I charged my battery and all has been good since. If in the future I go an extended time without my rig and have starting issues I'm guessing I'll find myself back here looking for answers, so please share your results lol.

So it seems they found an issue with the "controller", I'm assuming the ECU. I will find out more soon and update but I'm glad they found it and are taking care of it. I'm anxiously awaiting my "new" ride.

 

[SlcHummer]

So it seems they found an issue with the "controller", I'm assuming the ECU. I will find out more soon and update but I'm glad they found it and are taking care of it. I'm anxiously awaiting my "new" ride.

Have them order a tuned one from PCM of NC http://www.pcmofnc.com/product/hummer-h3-mail-order-tune/. I just installed mine and am now doing the security relearn process lol.

 

[Reloader]

A bad diode in the alternator can cause a battery to discharge over a period of time. The alt will still charge ok. Set your DVOM to A/C volts and check across the battery terminals with engine running for a/c voltage bleeding through. Anything over say .3 volt is an issue. Saw this a lot on GM vehicles over the years.

 

[adventuredad]

So the dealer finally got there act together and got the truck finished so I could finally buy it. They ended up replacing the PCM and the BCM. Unfortunately I had no control so it's not a PCMofNC which is on the list in the future. They couldn't tell me exactly what they found or suspected of the battery drain but hopefully something in there has fixed it. Now that the "new" truck is home I have to spend some time removing and fixing some of the wiring that previous owners did for radio and sub woofer. The backup camera is finicky as well so probably replace it and do a better job on it. I find more little "hidden gems" everyday that I look at the truck. I'm not ruling out the Onstar module or aftermarket wiring for the battery drain, gonna keep an eye on things closely for awhile.

Thanks for all the help!

 

[WildZ]

Has anyone had trouble with a mystery battery drain? I’m looking at buying my first hummer and went to the dealer to check it out today. They had it at the Chevy dealer to get checked out because when it dat for several days the battery would be dead. After jumping it, it would run just fine and if they started each day it would be fine.
The test equipment estimates it would drain in 7-8 days of no use.

The previous owner put in an aftermarket stereo with a sub in the back. My guess is that there might be something wrong with that wiring but they are working on trying to find the issue.

Just thought it would be worth asking the group to see if anyone has dealt with a similar issue here. Thanks for the help.


Sent from my iPhone using Tapatalk

I had a battery drain issue with my '06 H3 even after buying a new Red Top a couple of years ago. I unsubscribed from OnStar recently and haven't had a problem, starts up immediately after sitting a few days or a week. GM replaced OnStar modules in quite a few of their vehicles over the years because of outdated OnStar equipment, there are several links pertaining to this. Figured that might be the same parasite found in H3's battery drain, got lucky. Some have pulled the OnStar fuse/module out completely but so far I haven't had to do this, simply unsubscribing did the trick.