Constant Draw on Battery

Every couple of weeks I end up with a dead battery.

I pulled the positive battery cable and put a volt meter between it and the post (key out - everything off) and it was reading 12+ V - when it should read Zero V.

I proceeded to pull every fuse and relay - one at a time - and last but not least - pulled of forward "mega fuse" wire and voltage went to zero. So something on this line is draining current - but I can't find any info on what items this line feeds - or where it may possibly have a wire rubbed raw and contacting the frame..

Truck has lead a pretty easy life - parked outside - coast environment, but no rust - corrosion - or outside or undercarraige damage.

Anyone have any answers or suggestions - or have this problem in the past?

Thanks.
 

Blckshdw

Moderator
I don't know much about your platform, but on ours, the megafuse feeds a second fuse block inside the cabin (under the rear left seat) Does your truck have one of these also?
 
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CoastalTrader

Member
Blckshdw said:
I don't know much about your platform, but on ours, the megafuse feeds a second fuse block inside the cabin (under the rear left seat) Does your truck have one of these also?
I have the 2006 Colorado 4 door quad-cab and just went and checked - no fuse block under either rear seat or front seats.

Thanks for trying.
 

Wooluf1952

Well-Known Member
If you don't use OnStar, disconnect the OnStar box.
 

n0kfb

Well-Known Member
CoastalTrader said:
Every couple of weeks I end up with a dead battery.

I pulled the positive battery cable and put a volt meter between it and the post (key out - everything off) and it was reading 12+ V - when it should read Zero V.

>snip<

Anyone have any answers or suggestions - or have this problem in the past?

Thanks.
You don't care much about the volts in this case... how many amps are being drawn after the truck has been off for a couple hours?

-- Dan Meyer :coffee:
 

Blckshdw

Moderator
As best as I can tell, the megafuse feeds the front block directly, so you may have multiple components with a current drain, that's why pulling them one at a time didn't tell you where the problem was. So disconnecting that, disconnected all of them. You may need to pull a handful of fuses at a time, and then see if the current draw drops to zero :twocents:



 
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CoastalTrader

Member
Blckshdw said:
As best as I can tell, the megafuse feeds the front block directly, so you may have multiple components with a current drain, that's why pulling them one at a time didn't tell you where the problem was. So disconnecting that, disconnected all of them. You may need to pull a handful of fuses at a time, and then see if the current draw drops to zero :twocents:
No power seat - no heated seats - no Onstar. Looking at the schematics - it looks like the 2 post mega Fuse are a battery feed and a generator feed. Leads me to think I may have a problem in the alternator circuit. Not sure of amp draw - but I think it is relatively small. Take a few days to draw down battery if its parked.

Thanks guys - looks like a visit to the shop - $$$$$$$$$$$$$$OUCH !

I was kinda hoping someone may have experienced this problem. So far I'm the guinea pig here. I'll keep checking back for more thoughts and ideas from you guys.

When I do get it fixed I'll post the results for you guys.

Thanks.
 

RayVoy

Well-Known Member
I know nothing about your platform; but, the check that you did with your volt meter is not the correct way to look for a battery drain.

I expect, that under normal conditions, the volt meter would always read 12 volts.

Your test, tells me that:
1.....your ground connection is good
2.....you have continuity through an electrical component.
3.....that some electrical component is operating in your truck.

If you have anything in the truck that requires the slightest amount of current (and the VOM is of a very high impedance), the meter will read 12 volts.

Anything could be a clock, a radio with presets etc.

You need to set up the meter in the same manner, but use an appropriate current scale to read the current being consumed; then pull fuses.
 
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CoastalTrader

Member
Problem solved - I hope.

Took it to the shop. The mechanic and I did a battery test first - and the battery was hoopped - Which is understandable being that it is 6 years old - and re-charged heavy a several time recently. They say you should change about every 4 years. Put a new battery in and then put the meter on it. Showed a draw - then current dropped down to almost nothing. Apparently the onboard computer (or whatever) keeps things on like your interior light, etc - and then when that shuts down the draw was minimal - and normal.

So I think we are good to go. If battery goes dead again - which I doubt - then there would be a short somewhere. If it does I'll come back and carry on with the operation. Troubleshooting is a great skill set to have.

Thank you all for your help.

Cheers.
 

MAY03LT

Founding Member
Lifetime VIP Supporter
Thanks for following up with the fix!:thumbsup::cool:
 

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