2002 Chevy Trailblazer Battery continues to die if left ove

ERICHEAVNER

MEMBER
2002 CHEVROLET TRAILBLAZER
6 CYL
2WD
AUTOMATIC
130,000 MILES

I seem to have an electrical drain. I have replaced the batter and the alternator checks out fine. If I jump the car, I can drive all day. It can sit for quite a while and upon return, starts normally with no noticable delay. If I leave the car overnight, the battery will completely drain to the point that it won't click and no accessories will come on. My previous battery was 4 months old and I just got a new battery a week ago. I would think the alternator is bad but wouldn't the car eventually die after driving for a while if the alternator were out?

All electronics seem to work normally. I have no burned fuses, (check them all) and nothing appears to be on when I turn off the car. I've even snuck into the garage late at night to see if anything is lit but the only light I see is the intermittent flashing of the security system LED on the radio pod.

Help. This is driving me crazy and I'm not to happy about letting the dealership blindly poke around for $85 an hour.

Thanks,

Eric

5 Replies

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

You will have to have a current draw test done, place an Amp meter between there Battery pos (+) terminal and the cable, and check the current draw with the doors closed & key out, you will have a small draw for radio ECU of about.15 Amps, if higher pull fuses & fusible links one at a time to locate the defective circuit. Start here.

Mark (mhpautos)

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Monday, November 17th, 2008 AT 4:17 AM

ERICHEAVNER

MEMBER
3 POSTS

Thanks Mark. I'll give that a shot first. Since I posted my question, the car will not turn over at all now. All lights and radio, headlights, windows, etc, will operate but not starter. It's like the starter isn't even getting power. I've replaced the ignition switch but no luck. I guess the starter is next, then the drain testing.

Thanks,
Eric

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Saturday, November 29th, 2008 AT 8:21 AM

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

With what you have posted, I would be checking the starter and the starting circuit.

Mark (mhpautos)

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Saturday, November 29th, 2008 AT 3:15 PM

ERICHEAVNER

MEMBER
3 POSTS

I have used a multimeter and pulled every fuse. I can't see any significant drain on any fuse I pull. There was an initial drain that settled down to about.06 amp after a few seconds and this never appeared again during my test.

Test was done with key out, doors and windows closed and the multimeter on the hood where I could see it from inside when I pulled the BCM fuses. I literally pulled every single fuse and relay under the hood and back seat.

I replaced the key switch since it was only 30 bucks but I still have the drain and it seems to be getting worse. Previously, it would take all night to die, now it will die in about two hours. The battery checks fine, the alternator checks fine.

Anything else I can look for?

Thanks,
Eric

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+1

Saturday, January 17th, 2009 AT 11:10 AM

HULADEEZ

MEMBER
1 POST

I have the same problem with a power draw that would kill the battery overnight. I did some troubleshooting of my own and narrowed it down to fuse 31 in the owners manual. So, whatever it is that runs under the wiring bundle (Modules, servo's, switches, etc.) Of fuse 31 is causing my draw. Keep in mind when running your fuse/ wiring troubleshooting you would have to wait atleast 15-20 mintues(guessing around) for the modules to go to it's sleep mode.
Hope that helps, atleast enough time to save money to get it fix (which I'm currently doing ;))