2003 Hummer H2 battery dead again!!!

it sounds to me like something is draining your battery,
first of all lets check for a drain from your battery:
1. remove your + battery cable,
2. take a test light and hook it to the +cable and the other end to the post of your battery, if the test light is on you have a short,
3. make sure all the doors are closed, and you don't have a light under the hood staying on,
4. it will probably take two people to perform this operation, (only because you are a rookie) have one person look at the test light, if your fuse boxes is under the dash, make sure you hold your finger on the door jam switch that activate your dome light,
5. remove the fuses one by one, when the test light goes out you found the circuit that is giving you problems.

It sound sike you may have a defective battery, I would try a new one.

Some thing to check if you haven't resolved the isue yet is the electronic control module. I had a similiar issue with dead batteries and that was the issue.

[quote:a4e0787f92="hummerH2"]Electrical problem
2003 Hummer H2 V8 All Wheel Drive Automatic 64000 miles

truck died 6 months ago...had the hummers' system checked and it wasnt the alternator or starter..it was the battery,so i replaced it.now truck having weak starts (to point where clock resets each time).manuel says warning should appear on DIC that battery not charing ....but isnt? what is causing the dead battery?could this be a bad terminal ?... relay?...fuse issue? also front heated seats will not turn on,is this a conjoined problem with battery not charging.rear heated seats work fine. i found nothing of fuses for frnt heated seats in the owners manuel any where ,but did for the rear heated seats.[/quote:a4e0787f92]

Now that I had plenty of time to think about it.......I remember a suburban when I worked at the dealership, it had the same problem as your Hummer, I took the whole thing apart, unplugged every possible thing that could be draining the battery, and the very last thing I unplugged was draining the battery and that was the OnStar, some other dealership had replaced it and they put the wrong one in, (The numbers didn't match the computer) which was causing the drain, something to think about.

My 2006 H2 did the same thing then we noticed we could slightly hear the nav disk still running after the vehicle was shut off. Once we removed the nav disk and only inserted it when needed we no longer had the problem with the battery again. possibly caused by scratches in the disk and it kept trying to read it or something.