Ok, basics first...
My Camaro was driven daily for about 3 weeks since installing a new dome lamp, window motors, and rebuilding the door guts. I hadn't had any problems and the wife last drove it Friday, no problems. Today, the car wouldn't turn over, no lights, nothing. I got home, checked the battery and found it had 6.45 volts and 138 CCA. I bought a new one, installed it, it was reading 13.55 volts and 772 CCA at rest, the alternator is pumping out 14.52 volts and 82 amps at idle, 108 at 1.5K RPM. I turned the car off, removed the key, closed the door, disconnected the positive cable, made sure the hood and interior lights were off, and am still reading voltage between the cable and battery. I started pulling fuses and circuit breakers one at a time (with the door lamp switch disconnected) and could not isolate a circuit drain. I checked the brakelamps, not stuck "on", I'm not hearing any motors running, I can't find the current draw. Am I doing this right?

 

it's probably a bad ground, most likely at least i would check them and replace anything corroded

 

you dont disconnect the positive termional you disconnect the negative terminal. you decrease the chance of igniting the fumes from the battery this way.
the other reason is so you dont ground out your systems by touching the positive terminal to the frame.
this is just a safety precaustion and not an actual solution to your problem.

 

This is a very easy task that anyone can do and all you need is a test light..unhook the negative cable from the battery .Hook the clip from the test light on the negative battery terminal..and touch the negative post on the battery if the test light is illuminated you have a drain.Assuming you removed the hood light ,closed all doors, dome light off etc.Then start removing fuses until the test light goes out.The fuse you pull is the circuit that is causing your drain.Hope that helps some

 

That is nowhere neer as accurate as a DMM. 150mA = BAD. Do you know how much power it takes to light the bulb? It could be a lot more than that... If it did light, I would want to know by how much so I could search for the problem.

 

Not everybody owns a DMM..trying to keep it simple...

 

<---That is how I do it. However, if you don't have a test light, you can touch the neg cable to the neg battery post after you pull each fuse-if the cable sparks, you are still drawing current.

 

that is incredibly dangerous never do that.

 

I did all of this, except I used a Sunpro diagnostic multimeter (serves the same purpose) when checking the draw. I've pulled not only the fuses 1 by 1 but even the power window circuit breakers, nothing eliminated the draw.

 

If you have pulled all the fuses one at a time and are still showing a current draw, then it has to be between the battery and the fuse block. (Unless there is a circuit that bypasses the fuse block and uses an inline fuse or fusible link) If it were me, the next thing i.... Interseting.....I am not sure why this posted here partially and then again completely just below.

 

Try disconnecting your alternator wiring and test again for current draw.

 

If you have pulled all the fuses one at a time and are still showing a current draw, then you know it is probably between the battery and the fuse block. (Unless there is a circuit that bypasses the fuse block and uses an inline fuse or fusible link) If it were me, the next thing I would do is get the wiring diagram (possibly at your local library?) and begin tracking any routes between the fuse block and the battery. I can tell you from my experience that I have found things such as nitrous bottle heater left on, rear hatch trying to close, under hood light, etc have been sources of this type of issue for me in the past. As far as your original question, I would say you are "doing it right". Good luck.

 

I was going to type out a big reply but Doc Vette from Hotrodders is the pro and he already typed it all out so here is a cut and paste that should help you out.


To test for battery drain..

remove one battery cable, be sure everything is off,

Configure your meter for AMPS, set to the highest scale (usually 10 amps),

place your meter BETWEEN the cable and the Battery post..scale your meter BACK as you read your readout, until it just barely pegs the meter..

That will be your true static draw.

It should read between 0.3 and 0.8 (less than an amp) If you have anything with computer presets (CD PLAYER memory) or a Mechanical or Digital clock..and ECU.

Above that you have a problem..Remove the wires from the alternator and test again, If it drops or goes away, your diode pack has forward biased itself, (small drain forward) and is your source for drain..replace the diodes as needed or replace the alternator.


If it persists after disconnecting the alternator, If your fuse buss is well marked, pull all the fuses and relays..

replace them one by one monitoring the meter, until the current jumps up..that branch circuit is the offender..

troubleshoot that and repair as needed.

If it is not marked, make a sketch of it showing location and fuse values (and save it for future reference.) With all the fuses out..check them all with a DVOM on Ohms , scale R X 1 , calibrated 000,

DO NOT trust your eyeball, a filament can open at an extreme end and you won't be able to see it..EVEN though this is not related to the problem, you'd be surprised how many you may find open, and Stuff that starts working again when your done!

hope that helps
Ric

 

I didn't check the alternator diodes yet, I bet that's it!!!
THANKS, guys!!

 

Don't want to hijack the thread but I am having the same problem. Today I got a new battery and a new multimeter (my old one was shot). I have the scale set to DC Amps on the 200m scale. It's reading about 7 on that scale. Is that more than what it should be?

 

FOUND IT!
I did have the alternator diodes checked, they were fine. The drain was from the hood lamp! The strut-tower brace was smashing the hood-lamp when closed and it had started wearing a bare-metal spot wear it contacted the lamp housing, evetually hitting the positive contact!