Hello all, I'm new to this site and new to the Hummer world. Just last week, I bought an 07 H3. Love the truck to this point. Unfortunately, throughout the course of the week that I've owned the truck, I've had some problems with it. Minor problems included replacing a brake light bulb and also dealing with the sun-roof leak which doesn't seem too uncommon from what I've read. The bigger issue now though is whether or not I have a dead battery. Last night, I was sitting in my truck after I had shut the engine off with the radio was still on(doesn't shutoff till door opens). I opened my door, shut it again and went to start the engine. When I did this, it started clicking, lights would go dim and I would hear a pop in the radio speakers. After a second or two, the engine would slowly start to crank over and eventually start. Every time I start the engine now, I notice the time on the radio resets back to 12. Today, I hooked jumper cables up to another vehicle to see if it gave it juice and it did, the engine fired right up. The truck only has 28.5k miles on it. The truck was bought from a dealer and is still covered under warranty. Any information regarding my issue is appreciated. Thank you.

 

Most likely a bad battery. Could be a bad alternator not recharging it but most likely its a bad battery.

Take it to an auto parts start and have the battery benched. If it's the OEM battery its probably bad. Those OEM wet cells suck bad and are only like 550CCA.

 

First, Check your batter terminal connectors!
If you can wiggle them at all they are way too loose! The OEM terminals are for ****, most of the H3/H3T guys/gals I wheel with have replaced them with high quality terminals and that has made a huge difference is the amount of power comming from the battery.

If they are not loose, then you prob need a new battery. It is a common problem on a lot of vehicles with all of the heat in the engine bay on a modern vehicle.

Hope this helps!