Electrical drain on a 03 Trailblazer

[max 02]

The battery will go dead after a few days, the battery is newish and in good condition, the alternator I have tested and it tests good many times...but I also have tested it and it showed bad twice?

I remove the ground from the battery and with a 12volt test light it will shine brightly, even after half an hour while I made sure the computers where all powered down. I have pulled all the fuses one at a time from both fuse boxes and removed the three fuses from the command start.

There is no other aftermarket accessories on this vehicle.

I don't have a multi meter or do I even know how to use one if it did.

Any ideas on how to find the drain?

 

[paratrooper307]

To do it right, you will need a multimeter. The reason being is because all vehicles will pull a little juice even after shutdown, and you're going to be testing for amperage, not voltage. A multimeter can also tell you the size of the draw, giving you a better idea of where to start looking. A circuit light isn't ideal, but you can use it and you're on the right track.

Here's how:

http://www.wikihow.com/Find-a-Parasitic-Battery-Drain

I'd probably write off the alternator as a problem, since a shorted diode will drain your battery quick, but check anyway. It's probably a bad ground or a short, but isolate the circuit and you'll at least find where to look. Don't rule out a bad battery that can't hold a charge either, sometimes even new batteries are faulty. If you've checked every circuit your issue is likely a ground or fusible link issue.

 

[Cili]

If your test light is shining bright with everything off that's a pretty serious draw. Leave the hooked up and unhook the power wire from the back of the alternator and see if it goes out

 

[max 02]

Thanks guys!

I'll try both your ideas.

 

[max 02]

If your test light is shining bright with everything off that's a pretty serious draw. Leave the hooked up and unhook the power wire from the back of the alternator and see if it goes out

Had to remove the alt to get to the back of it.
Still the same. X that test off the list.

I'll try the fuses one more time sometime this weekend... if the doesn't find it I'll buy a multimeter and try again.

Should have bought one years ago anyway.

 

[max 02]

I forgot the update this...

About a month ago I was pulling fuses again and found the ignition switch fuse to be drawing, I replaced the switch but still had a draw.
Then we noticed the brake lights not working. One of the lights had a burnt up circuit board, we replaced it with one from a auto wrecker and it has been starting fine ever since.

Honestly I never checked for a draw again after this... It starts we are happy.