My girlfriend has an 02 trailblazer that will work for a day and be dead the next day, has a new battery and alternator is good we got it check out, we even took the fuses out for the raido and it's still dying, any guesses on what it might be? Thanks

 

Check on you tube for parasitic draw videos. It will show you which circuit has a problem. If you find the circuit but not the problem. Let us know.

 

Drains like that can be a bitch to figure out. We bought a cheap battery disconnect switch for mom's jetta til we found the one on hers. Better than draining and killing a new battery.

 

My 97 did that too. Turns out my power lock switch was bad and it locked unlocked locked unlocked my car all day or night. Killing my battery. Sometimes would lock me in or out of my car!

 

I have another scenario, my truck started misfiring one day as I pulled in to work, when I'm. About to leave the truck almost didn't started(weak battery) I put a new one as old one was dropping to 10-9 volts in like 1/2 hour. Replaced the battery still misfiring so I stopped using it then 3 days later battery totally dead. Jump it ran a scanner p0122 tps low voltage and after a few days trying to troubleshoot the truck I had a short on my tps wires draining my battery thru the night. This might not be ur case but just showing you that it can be anything, run a live data test and see if there's any sensors that aren't working properly, also see ur batt voltage drop after charging it, and to be sure disconnect it completely from the truck, if it still drop voltage being disconnected then it's ur battery. Good luck

 

My 97 did that until I replaced the alternator. The previous owner could never find the problem and he was a retired mechanic. I'm not sure how long it had been happening but a week after I got it started after 4 years of sitting the alternator started over charging the battery. It fried itself the following day and after changing it the problem stopped. It's been 3 weeks now. Check for over charging. There's a resistor that only allows the alternator to charge the battery. If it goes bad power can be drawn from the battery back to the alternator while the engine isn't running. It's rare but possible. It can indeed be found with a parasitic drain test.