First, I live in a very rural location, no Vette dealerships. I'm the trouble shooter & I best be able to tell the non Vette GM dealership what to do & how to fix it! I would not trust any of them with my car.

This car will kill the battery in 1 week, yes I've replaced the battery 2 times & yes I've made sure my aftermarket items are disconnected.

Here is what I've learned. Connected my DC current meter in line with positive cable from the battery. Cycle the Fob with the lock/unlock watching the meter, within a reasonable period time (minutes) the draw drops to .080 amps or 80 ma. All good, with another meter I check the DCV across the battery, just over 13 volts. I cycle the doors again, drops to 80 ma, I move the Fobs to another part of house, hopefully out of range....no change.

I leave it like this for a few days, check the current draw each day, .080 ma. I also check the battery voltage with a separate meter so I do not interrupt the circuit.

Well five days have gone by, still shows .080 amps, DCV has drop to approx. 12.4 V still more than enough to start the car.....WTH?

So day #6, I turn on the DCA meter, .250 Amp, check the battery voltage, 12.14 V. Then all of sudden the DCV meter drops under 12 VDC, I look at the current meter 4.0 A. It sits there for a bit, seconds then slowly drops back down to .250 A. I grab the Fobs, take them another part of the house, no change. So it will do this ever few minutes, cycle up to 4.0 A then drop back to .250 A. Never will it go down to .080 A like it did for the first few days.

I can even imagine trying to explain this to a GM dealer, the deer in the headlights look!

Can anyone help with this?

I purchase this car 2 years ago with 1350 miles, the problem was there then just intermittent. It now has 2600 miles & will kill the battery very frequently.

 

Well, a few things jump out at me right away. First, you have owned the car 2 years and driven it 1000 miles. Even a car without any kind of closed-circuit draw problems will kill batteries when used like that without a battery-tender or similar equipment.

It seems like the battery was in a decent state of charge when you started the draw test, but I'd suggest making sure it is completely charged and that it doesn't have any issues. How old is this battery and how many times has it been discharged?

As far as the 4 amp draw goes, something in the car is "waking up" when this happens. The strange part is that it does not do this until it has been sitting for a week, is that correct? 50 MA is usually a good number to shoot for, and even your regular sleep mode reading of 80 MA is on the high side.

As far as diagnosing the problem, you are going to have to eliminate circuits one-by-one. I'd suggest opening both doors and latching the strikers so the body module thinks everything is closed. Then you can access the fuse panel in the passenger foot-well while the car is asleep. When the problem is present, you will want to pull fuses until your problem is eliminated. Just do it systematically and pay attention to your DVOM readings.

Also, I'd pay real close attention to anything going on during this 4-amp spike. Are any of the interior lights coming on or the green circle on the start button? Could maybe be something like a defective door handle constantly waking the vehicle. I've had a similar problem on a '08 BMW 750I that I was working on. But really, it could be anything.

It can be tough to track these things down. You said you already did, but make sure any aftermarket stuff is completely disconnected. 4 amps is a big draw, so it is likely an issue with the vehicle being "woken" from its sleep mode. What is causing this is another story. Good luck and let me know if I can help at all.

Andy

 

Manual Trans or Auto?

06 auto had an issue with the trans not talking to the BCM and killing batteries. They can fix it with a flash. If that's it..............

 

Thanks for the comments Andy.

I should have qualified my comments a bit more. I've owned many Vette's over the years, currently a C5 & 6. So I have more than 1 Ctek tender & battery charger, even more than 1 GM Delco battery. The 2 GM delco batteries sitting on my shelf, I can charge, load test, let sit for months, load test again & they are perfect.

So I have many batteries, tenders, charger & a load tester.

Yes the battery in the C6 was fully charged prior to my test.

The 4 amp spike is the problem, the funny thing is the way it repeats itself. Excellent tip regarding pulling fuses to find the offending cct.

I immediately checked for interior lights etc. when it happened. I'm not 100% sure if looked at the Green on button, I know I looked that direction to see if the Red LED was still flashing.

The only aftermarket connection is to my battery which I made sure was disconnected.

Your suggesting regarding the door strikers, do mean just flip the door latch?

 

6spd

Tx's

 

Yeah, just flip the latches with a screwdriver so that it is like the door is completely shut. This way the door is actually open but the modules in the car think it is shut and will power everything down in a normal manner. You should hear the windows index up (if the glass is closed) when you click the latch all the way. That's a sure way to know the BCM thinks they are shut.

It is what I always do when chasing a draw. Gives you access to inside the car without climbing through a window Dukes of Hazard style

 

Oh, and I also wanted to add that I've always done draw tests by hooking up inline with the negative side of the battery. Not sure if it really matters.

 

Current flows from positive to negative, but I don't think it should matter.

GM has a device referred to as a "flight recorder" that is can be attached to circuits in the fuse box that can tell you were the drain is coming from. The device is made by Midtronics in Hinsdale (or that general area) IL.

http://www.midtronics.com/home/produ...ata%20Rec.aspx

 

On a C5 there are a couple of things that Ive seen that fail to shut down and cause excessive current draw. They are

Seat multifunction control switch
Lumbar motor

See if there causing you issues.

BC

 

DBS with '05 MN6 was a 24-48 hr battery kill, not a week.
But with the few afflicted early '06's I'm not sure.

 

Only auto trans in 06, manual in 05.

 

Tx's for the tips!

I'm going checkout midtronics as well.

 

I'm seeing this a little differently....I did a check on my battery drain a while back and found that mine draws between 11 and 17 ma from the battery after it is given a few minutes to calm down. Also, the draw is constantly varying between 11 and 17 and is not static. So I do not think that the 4 amp spike is really your problem, I believe that your 80ma draw is too high to begin with. I think that the level of the steady draw is more important in killing the battery than the spike once in a while. Also, the location of the fobs being near the car or far away should be meaningless if the system is working correctly.

Here's an interesting thread on current draw from a while ago.....

http://forums.corvetteforum.com/c6-c...-problems.html

 

Yeah, but 80 ma shouldn't kill a healthy battery that quickly. Most of the modern cars I work on with a lot of electronics have the acceptable limit around 50 ma. I also think that 80 ma is on the high side (as I stated in my original response above), but it does not seem to be the cause of his real problem.

His real issue seems to be that after 6 days of the car sitting idle, something wakes up and he gets a 250 ma draw, which will cycle between 4 amps and back down to 250 ma again. My guess is that it keeps doing this until the battery goes dead, which won't take all that long.

Again, I think an 80 ma draw is less than ideal, but the real issue is the wake-up/spike. This comes from years of being a professional "gremlin chaser" on high-end cars.

To CTD (OP), does the battery still go dead even if you have a tender on it in the garage? Just curious as you said you used one.

 

Midtronics makes some good stuff. In fact, they make the battery tester I use in my shop. The tool that was linked, though, seems like it is just a multimeter with data logging capabilities. I use a amp clamp and our diagnostic equipment to record draw patterns when I have a really strange issue like a random wake-up problem. The main point of this is to find when the draw problem is present and how many MA the draw is. You have really already done this. Now you just need to figure out what circuit is causing it.

The ability to hook it up to individual fuses would be cool, if the midtronics tool can do that. Especially if it can do it without disturbing the circuit. I think for you, pulling fuses should suffice.

Keep us posted.

Andy

 

With a Tender the battery stays up just fine, never a problem.

The 80 ma maybe Hi, 40 - 50 ma seems to be the norm from other posts. Regardless that will not flatten a battery in a week. It is the .250 ma & the spikes, I will pay more attention to frequency of the spikes this time & of course latch the doors open!

Possibly the two situations are related, I also have read that when the battery voltage drops then strange things really do that place.

I tried to find some info on that midtronics logger, I don't think it would be able to identify the offending cct though.

I read the link posted, my draws all seem to follow that poster's timing as it cycles down.

 

I agree with you...and I should have been more clear...I think that whatever is causing his 80ma draw is the root of the problem and is related to the spikes. If the 80 ma is fixed, I think the spikes may go away along with it. The 80 ma draw will drain the battery of one amp-hour about every twelve hours, so he is losing 2 amp-hours of capacity from the battery every day. The battery is on the smaller side of car batteries, so maybe its about 65 amp hours. losing 2 per day is significant...a battery loses its ability to start the car long before its amp-hour capacity gets to zero.

 

I'm in the garage right now connecting all the meter's. I drove the car Sat for approx. 1 hour

My battery voltage is already down to 12.25 v, the draw .160 to.170 A's. It is also spiking to 2.65 A every couple of minutes, nothing is lite up. Then it drops .170 to .180 A

Battery won't last very long like this.

So it appears a lower battery voltages aggravates the condition.

When I open then close the door 4.68 A draw, then cycles down to the .180 A

Cannot get draw back down to the .080 A like the previous test. Then I started with a fully charged battery.

I've read a bad diode in the Alternator can do this, I think this will be my first disconnect.

 

OK I disconnected the Alt. no change, I thought I would try pulling some the relays in the under hood just to get a clue, no change.

Then I latched the door lock as per instruction to gain access to passenger fuse area, still no change.

I took the approach again of removing the bigger relays & fuses just to try & get a clue, no change.

All right now it is time to start pulling fuses, started with door locks, no change, then the CTSY/LAMP......a change!

My cycled down draw had been steady @ .180 A, when I pulled the fuse it cycled down to .120 A. Not a huge change but finally a change. What normally happens is every 2 minutes something wakes up, a current spike to 2.66 A then it begins to cycle down, this time with the fuse removed it cycles down to .120 A then after 2 minutes it cycle down to .01 to .02 A.

Now the interesting part, it does not cycle back up every two minutes, now it takes 10 to 11 minutes before it spikes up then cycles down. The good news is it cycles down in approx. two minutes to the .01 to .02 A draw

There is nothing on I can see, I do have a vert so maybe I have trunk light on. My hood is unplugged so it is not that.

Any ideas on how to troubleshoot this area & clues as to what else is on the circuit would be very much appreciated.

This exercise really demonstrates how quickly the battery will discharge in these cars. I have no idea why the system will cycle every two minutes, however that constant spike every two minutes isn't good.

Thank you for tips & clues trouble shooting this, I've had this problem for 2 seasons.

It will be even better in the end if I don't involve a dealer!

 

It's not the trunk light as just one light bulb anywhere in the car would be more than the .180 draw. You need the wiring diagram to see where that fuse goes. As I said earlier, my car calms down to .011 to .017 amps of draw. Do you have any accessories in the car....M2W, cell charger, LED light bulbs...
You could see if that fuse supplies interior lights and then start pulling bulbs and see what happens....sorry I can't be more help.....