I have a H3 hummer but my truck battery keep going dead and my battery is new and alternator is good

it may not be a drain on the battery the alternator may not be charging at the correct rate , this will not always bring on the red charge light if it is just below the range , do you drive at night , use the A/C ,etc things like this can drain the battery whilst driving and not getting re-charged by the alternator.If the charge rate is ok then disconnect the earth cable and put a test light between the earth terminal on the battery and the earth cable , if it lights up then there is a drain , check any interior light that may be on all the time , glove box or under hood are usually overlooked , if no lights found then remove the fuses one by one until the light goes out , that will tell you what circuit the drain is from , then you know where to investigate , loose connection , worn wire etc keep me posted if you wish

go under it put power to the starter ,it will activate the system

Try charging the battery a bit by snaking the positive jumper cable underneath to the starter post where the big cable connects, and the negative jumper cable to a good ground on the frame.

I don't have a shop manual for a Hummer.
But GM trucks built in 2007 use something other than the alternator to control voltage. Sometimes its called a generator control module and sometimes it is inside the body computer or the ECM.
You may need to check with someone who specializes in Hummers for the answer.

I have a 2006 H3 and the battery keeps dyeing when I lock the doors. Has a new battery in it and have had this problem off and on since I bought it, but now it does it all the time. Any one else have this problem ?

six disc cd changers are notorious for not working in gm. vehicles. on the battery issue i would get a new battery first. the place you bought it from proly jus through some old battery that was layn around to get by. i had the same problem, the battery checked good but just wasnt the right size for the hummer. new bigger battery fixed it all. it could also be the problem with the cd player. my superchips wouldnt work till i got a new battery. hope this helps

MOST NEW GM CARS YOU NEED TO ERASE LOW CHARGE TROUBLE CODE FIRST USING A CODE SCANNER BEFORE CRANKING VECHICLE.IF ALL READY DONE CHECK ALTERNATOR BATTERY FEED WIRE AND VOLTAGE REGULATOR WIRES AND CHECK ALTERNATOR FUSE.

check for problem brake booster
vacuum leaks under brakes

I AM LOOKING AT ALTERNATOR.IF ITS FAULTY.IT WILL CAUSE PCM PROBLEMS AND MISFIRE TO ALL CYLINDERS DUE TO WEAK SPARK TO IGNITION SYSTEM. CHECK YOUR WARRANTY THEY MIGHT FIX IT.STILL A NEW VECHICLE.

well what could of happend they probably put the battery on backwards and blew out a fusible link.The links run thru the wires by the battery and behind the alternator check it out Good Luck keep me posted