I have a problem that I’m hoping someone can help me with. I have a 2008 Hummer H3 Alpha. When the hummer sits over night I initially have a problem starting it. It will turn over for a fraction of a second and then be completely silent. It will usually do this three or four times and then start. Once started; it will start all day long with no problems. I have tested the battery, alternator, starter and grounds; they all seem to be fine. The thing that has me baffled I guess is that once it starts, it will continue to start. If it was a bad ignition switch or relay wouldn’t the no starting be more random and happen throughout the day? A friend of mine thinks it’s some kind of contact problem that is hazing over when left over night and then burns off once started. Has anybody had this issue? I don’t think it’s the security system because I don’t get locked out for ten minutes and there is no security light on. The hummer also isn’t throwing any OBD2 codes. I’m hoping someone can help! Thank you!

 

I forgot to mention sometimes during the three to four no starts when I turn the key there will be no sound at all. No starter, clicking or any thing. However all the electronics work fine when this happens. Thanks in advance for any suggestions!

 

dont know. id monitor volts as u turn key to see if it drops, a load doing nothing?,,starter stuck?

 

Thanks for the reply Happythree! The volts while cranking drop to 10.5 and then shoot up to 14.4 right away. The battery volts before cranking is 12.5 The starter doesn't appear to be stuck or frozen, it spins for a second like the Hummer is starting normally and then everything stops complete silence. It will do this a couple of times and then start fine for the rest of the day. Its driving me crazy!

 

i mean look at volts when it DOESNT CRANK. if it drops,could be bad starter?

diagram shows a switch inside the started. it may stick, not pull in?
it would pull current, drop volts but not crank.

 

Thanks Happythree, I will try that when I start it in the morning since that's the only time it does it! I will post the results afterwards.

 

Are you still running the stock battery terminals? If so those are known to cause lots of different electrical issues.

 

I had a similar problem, wound up replacing the back half of the ignition switch. Easy ten minute job and was about 40 bucks off amazon.

 

Thanks for all the reply's! I did replace the stock battery cables a few years back. I will look into the backside of the ignition switch. I just cant figure out why it wouldn't happen all the time if it was part of the switch but I'm definitely not a subject matter expert in the realm of electronics!

 

I finally had to break down and take my hummer to the dealership. The dealership said everything tested good. A battery test did show that the amps were reading low so they decided to put in a new battery thinking it would fix the problem. It didn't fix it, when I went to start it this morning after it sat over night I had the same starting problem. It will turn over for a second and then complete silence! It will do this a couple of times and then start all day long with no problems. I have spent hours on every type of GM forum you can imagine trying to find an answer to this problem. I'm really hoping someone can help me with this! Any thoughts?