Ok, this has happened twice now, where my 2008 H2 doesn't start. It seems like the battery is dead, I need a boost, then it's fine. I had on star do a diagnostic and they say the charging system is working fine, maybe the battery is just no good.
Has anyone had trouble with the battery draining while the vehicle is parked?
A buddy told me that the computer takes quite a bit of power and if you don't drive it often and for longer than a quick trip, it will drain the battery.
I'm going to bring it in to the Hummer dealership and get them to test the battery.
Maybe there is something electrical that isn't shutting off, I don't know, but it is very annoying!

 

It might be a bad battery. I have a 2008 H2 also and have had the battery replaced twice. Fortunately under warranty.

 

Sounds like a bad battery..my 05 has the original battery and its still good..I may not start my H2 for a week or more but it always starts..it has turned over slowly when it has sat for a 10 plus days but so far it has always started..if you have an 08 I would suspect the battery first..

 

I put a trickle charger on it last night, and this morning it was fine.
What does your volt meter read when running? Mine is below 14 maybe 12 or so.
There is not even 5000 km on my H2, I'm wondering if this is a bad sign!?

 

12 to 14 volts.....shes charging! How often do you drive it?

 

It is possible that it is not the battery, I just had the same symptons, I thought it was the battery but was charging ok, and tested ok. it was a weak starter. I got a new starter and its all good now.

 

I don't drive it often, and when I do, it is usually short trips. Is it possible that I'm not driving it long enough to charge the battery from the drain of turning the engine over? It does sit in my garage for 2 - 5 days sometimes. I wonder if the On-Star system is draining the battery enough to give me trouble?

 

Any aftermarket electronics? Any work done on wiring? No battery should go dead after sitting for 10-15 days....or more. If it's being charged it is one of two things.

1 - Bad battery. Pretty simple to check at the local dealership or auto parts store..if not under warranty.

2 - Slow drain on the battery=something is shorting out, drawing power even when the vehicle is turned off and idle. Can be bitch to track down a wiring issue

My '72 'Cuda will sit all winter (Nov thru April) and only get started every 4-6 weeks. It has never failed to start in 10 years I've owned it. Strong battery and no shorts in thw wiring....

Cheers,

 

Totally stock, nothing aftermarket. I'm calling the dealership today.

 

It is a simple test to check the battery...bet that is your culprit!

I had a '98 Taurus SHO that ate batteries...was bone stock, but there must have been a short somewhere. As with your H2 the SHO was under warranty and I got three new batteries in 28 months.....annoying but didn't cost me anything...

Good luck,