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CityMoto 07-17-2013 10:25 AM

Battery Drain!! Going Crazy!!
:confused:Hello all! I am a small independent dealer in VA. I specialize in Wranglers. I have sold a lot of Jeeps and of course have owned several and love them!
I now have a Jeep that has me very puzzled! This is a 2004 Rubicon. It is a 5 speed and has small lift. It only has 54,xxx miles on it. It WILL NOT hold a charge. The battery will last for about 2 day and then is as dead as a stick!! Again, I have been selling Jeeps for about 15 years. This one has me stumped. I have had several techs look at this with me. No one can figure it out. Here is what I have done so far.....
Took meter to battery and removed every fuse one at a time looking for a spike. Did the same for every relay. Replaced alternator. Replace battery twice with new battery. Took battery out of another jeep in stock and swapped, the battery performed well in the other Jeep. Replaced AIC. Swapped starter to another Jeep.
NOTHING WORKED!! Please help guys! I am considering a new Engine Computer (PCM/ECM/ECU) from All Computer Resource inc. If this is the next step, has anyone installed a new PCM?
Thanks in advance for your help!

Ferrachi 07-17-2013 10:44 AM

Is there aftermarket lighting, winch, etc? I had the same problem on a RZR and it turned out to be a faulty aftermarket light. Otherwise, I would be looking for draws with my multimeter, as it sounds you're already doing that. Hopefully someone else will chime in.

CityMoto 07-17-2013 11:42 AM

No aftermarket equipment.... Thanks anyway... hopefully someone with know something lol

Jerry Bransford 07-17-2013 11:48 AM

What type of meter are you using to look for that 'spike'? If you're using a volt meter, that won't happen. You're looking for an amperage draw 'spike' which can only be detected by an amp meter inserted in series with either battery connection.

Remove all the fuses, then insert the amp meter in series with one of the battery leads. Installing certain fuses will cause an immediate small battery drain like those that provide power to the ECM and clock radio. Look for an amperage jump from different circuits from those.

Did the previous owner install anything like a big stereo amp, a battery isolation relay, etc.?

CityMoto 07-17-2013 02:37 PM

We used a multimeter. It was looked at my to other ASE techs. I am not sure what they used but the last one narrowed it down to the IAC or the ECU. We replaced the IAC and 2 days later the Jeep was dead again. I am afraid we are down to the ECU unless there are other ideas. There was no aftermarket stereo. Thanks for you info.... any other advise??

Jerry Bransford 07-17-2013 02:41 PM

Yep, make sure your tech knows how to use a multimeter and its amp meter function. If he just used the volt meter, it wouldn't have helped. Multimeters include a volt meter, amp meter, and ohm meter.

1HUNTS69 07-17-2013 02:53 PM

Had the same issue for about three months, dumb as it sounds come to find out the under the hood light was coming on. My jeep is not my daily driver one night after I came home from work saw a glow under my jeep looked under to see the light on disconnected it never a problem since.

PhulesAu 07-21-2013 08:21 PM

Optima instruction state that KEY OFF drain should be about 25 mA , 100 mA is considered "excessive".

AtomicDog 07-21-2013 08:52 PM

Connect an ammeter to the battery and cable then disconnect the cable. You want to see the draw when everything is in the normal off state. The other option is to connect the ammeter between the battery and cable then let it settle down. The hood light is a good item to check. Just disconnect it if nothing else. If there's a drain on the battery you will see it on the ammeter. Pulling fuses works if you can see the drain and want to see what pulled fuse makes it go away. Kind of the opposite of a spike.

MoparMech 07-21-2013 08:59 PM

You might have to disconnect every module that is on the bus. But if your tech narrowed it down to the PCM. I would replace the pcm. I'm a Chrysler certified tech and It pisses me off when the managers don't listen to us. So listen to your techs.

jtholst66 09-20-2013 02:04 PM

I'm having the same problem. Brand new battery and brand new battery cables. Alternator checks out fine. I disconnected the negative battery cable and measured 12.75V from negative post to negative cable. Then, I started pulling fuses and measured the voltage after each pull. I noticed voltage drops on the radio and MSFW fuses, With all fuses out, I read around 3.1V, is that normal with all fuses pulled out? When I started putting the fuses back in, the MSFW fuse caused the voltage to jump to a 9+. Took that back out. The radio fuse caused a jump to 12.75V. Same with the Access 2 fuse and ASD fuse. It takes 2-3 days of absolutely no driving for my battery to drain. Any idea what is going on? I was hoping I would be able to narrow this down to a single circuit but this method made me more confused!

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