I've been having issues with my 2002 blazer starting after sitting for a while. Figured it was a mild power drain, would get to it when I got to it. However, after giving it a good jump and then driving it to work (30 miles there, 30 miles back) the next morning it wouldn't start. It tried to crank a little, then clicked a bunch at me. Took my girlfriends car to work as I was already running late. Just got home and tried to start again. Same thing happened except as I turned the key and it did the same clicking routine, my rear hatch opened...? Got out and closed it, then got back in, tried to start and it did the same thing. Is this common for simple dead battery issues? Why would my rear hatch open? Any ideas on where to start figuring this mess out?

 

I once had the same thing happen in a Blazer when the battery was going bad. Replacing the battery solved the issue.

 

I agree with rriddle3 on the battery. It's disappointed you 3 times. If you're concerned something killed it, do a parasitic drain test with a known good battery.