I have recently been having trouble with my 97 6spd vette. Within 5 to 7 days, the battery completely drains out.

I have spent the last week trying to locate the battery draining source. To do this I connected a multimeter in series with the battery and measured the current through the meter. The car initially draws about 2.2A but after 15min it draws about 0.3Amps. I tried pulling fuses from the engine compartment, but none of them affected the current draw. I then pulled fuses from passenger's footwell fuse box. Neither of those fuses seem to affect the current draw either. I disconnected the 12 disc changer in the trunk. I also checked the alternator for any leaks but none were present. I had a hunch that maybe it is the TPMS/RFA module. I disconnected that module and still 0.3A draw.

The only clue I have now is that there is a very light hum coming from the dashboard. It is very faint but definitely present. I cannot pinpoint the exact source of the hum but is seems to be around the dashboard on the drivers side between the steering wheel and the radio. If anyone knows what could be causing this hum noise or something else I should be checking then please let me know. I am running out of ideas! Thanks in advance!

 

You pulled every fuse in both fuse blocks? How bout the relays? Next disconnect the 12V feed to the IP Fuse Block, to isolate the power to inside.

 

Make sure you check you wires by the starter. I thought my alternator was bad since it was not charging my battery, but I had a bad wire by the starter that needed replaced. Fixed my battery issues.

 

Your battery is charged through the starter so I would check the wires from the alt to the starter. I had a bolt loose on my starter solenoid that caused my charge system fault code. If you look from the passenger side there are 2 bolts on the solenoid, one with a purple wire and the other with an orange, red, and black (I think). Check thos two. Also check your solenoid itself, it might have gone bad. Lastly it might be your ignition switch

 

Thank you very much everyone for the advice. I will check the starter and alternator more carefully. I will also check the relays in each of the fuse boxes.

If all else fails then I will pursue the buzzing noise coming from the dash. I'm hoping it doesn't go that far because I really don't like removing the dash.

Just as a side note, does anyone know an easy way to disconnect one of the battery terminals without constantly sparking the battery? This is one of the reasons I don't like side terminal batteries.

 

How old is your battery?

 

Might wanna check it at night. An incandescent bulb such as the interior bulbs pull exactly 280 milliamps.

Also, an inductive amp probe goes along way in isolating individual circuits that may or may not be drawing current. Using a wiring diagram and an inductive amp probe, you'll be able to narrow it down very quickly.

 

Thank you countylawdog. How old is the battery? I had some bizzare things occur with my car. I read this forum and found many disturbing issues. Then the one that asked "how old was my battery" came up. I went to the garage and now the car was totally dead. I removed the battery and the car started clicking. Got a new battery and everything was fine, no issues whatsoever. That dead battery was only 3-1/2 years old.

 

Is that hum noise on all the time or only present for a short time? That could be one of the a/c actuator motors stuck trying to reset itself or move to the default position.

No codes then for any systems?

 

with the kind of current draw you are experiencing, the battery will spark when disconnected. should be less when you find out what the problem is. i was lucky enough to have my battery drain problem solved by a new battery. what kind of voltage are you reading? i don't think 300 ma in sleep mode is ridiculously high and a good battery should support that load for more than a couple of days.

 

The battery is about 8 months old. It is reading 13.3V. The humming noise is present as soon as the battery is plugged in, and it never goes away.

I just bought a clamp meter. Hopefully it will work better than the multimeter in series. My gut feeling tells me that its the Bose audio relay under the dash.

 

it would seem to me that the humming noise would stop when you pulled the right fuse. are you sure it continued when you pulled the fuses? i have also read of problems with the electric seat motor continuing to run because of a sticking switch. use a long ratchet extension or even a doll rod to put up against components in your car and listen at the other end to try to isolate the source.

 

You are correct about pulling the right fuse. First I disconnected the body control module. Then I went through the fuses in the fuse box located under the passengers footwell once more. Turns out fuse #25 is linked to the current drain. As soon as I pull #25, the current drops to 0.02mA. I must have missed it the first time because it is linked to the BCM.

Fuse #25 is described in the manual as "Body Control Module - Ignition 1, Instrument Panel Control". I am assuming this controls the dashboard guages and stuff. I have a hunch that the chime device is the culprit (the sound device that tells you if you left your key in the car or left the headlights on). Does anyone know where the chime device is located and how to disconnect it? Any help is as always greatly appreciated.

 

It sounds like you have a service manual, so take a look at the wiring diagram for the instrument cluster. Minifuse 25 provides 12 volts to the cluster. Where does the chime come into this? Is the chime not working or making unusual noise?

http://www.flickr.com/photos/1545929...74901/sizes/l/

 

chime info.....

http://www.flickr.com/photos/1545929...40398/sizes/l/

 

Mine does the same thing and have never been able to figure it out. I think mine will set about a week before the battery is dead. I've noticed that when I connect the battery it sparks alot also.

 

Thank you lucky for the schematics. I unfortunately don't own a service manual (I will buy one very shortly). According to the schematic, anything in the Instrument Cluster could be leaking, not necessarily the chime device. Also, the chime device seems to be working properly (I tested it by inserting the key and opening the drivers door).

One thing I noticed is that the buzzing noise turns off when the chime is engaged. As soon as the chime is disengaged the buzzing turns back on (with a 1-2 second delay).

Does anyone have a detailed instrument cluster schematic?

 

PM me your email, and I'll send you what I have.

 

Looks like I found the source of the drain. It has to do with the Instrument Panel Brightness Control ****. The **** can be turned left or right to adjust the brightness of the instrument panel. However, if turned all the way to the left, a switch clicks on. This switch momentarily turns on the interior courtesy lights. After 15min, the lights turn off, but the panel still drains about 280mA of current, even when the car is turned off!

Either the switch in my car is faulty or GM has overlooked a flaw in their design. I had to go through a lot of trouble to find this problem. I just thank God that I found this before removing the dash. On the bright side, this is an easy fix (do not leave the switch on).

Thanks everyone for all the help. I can sleep a little more peacefully knowing my baby is ok!

 

i would have thought that your courtesy light would be on while you were driving as well with the switch locked on. glad you got it worked out.