Electrical Trouble Shooting

[apex]

Need some input on trouble shooting DIY.

I have a slow drain on my battery that kills it if my Jeep isn't run for 2-3 days.  So long as I turn it over for 10 mins every other day I'm fine.

I need to find the source of the draw/short. My plan is to put a test lead/light between the negative post and main ground, then start disconnecting every electrical connection I can reach until the light goes out.

My questions. Is there a logical place to start or an easier way to trouble shoot this? Would pulling fuses one by one at least isolate the offending circuit?

My spec. '02 TJ 4.0l,  Red Top Optima, stock Alternator, no electrical accessories except a security system which isn't armed.

Thanks in advance.

[Pookapotamus]

is the battery new? if not the battery could not be holding a charge. fuses would be a good place to start and would help isolate the problem if you have an ampmeter that can measure draw hook that to the battery then start pulling fuses.

[apex]

Yeah.. the battery is new-ish. 1 yr old. I had a similar problem with the last battery I had as well. The problem took 16 months to return telling me there is a small enough draw over time to kill the battery.

Good call with the ampmeter. I'll give that a go.

[jandh]

Here's something to be overlooked, now its a long shot, but it has happend to me before - Check the bottom of the battery, I had the same problem and found it to be on my brand new battery, which had a small hole in the bottom caused my a small bolt in the batter holder rubbing the bottom till it made a hole and grounded.
 
or

You may have a ground in one of your lights - if its grounded out it may draw power through the frame, but the thing is when you shut off your truck it should kill power to everything exept the ignition, so i think you have more of a battery prob or and alternator voltage regulator prob then anything

[apex]

Thank you all.

Tinkerer. On the trickle charge, should I avoid this if I have a deep cycle battery? IE Red Top Optima. Was thinking of getting a solar 5W trickle as a temporary fix until I suss out the real problem.

I was also thinking of measuring the draw using an ampmeter then trying to figure out what electrical device uses the same draw.

I was suspecting the alternator. I've had a LOAD of dirt up under the hood and never took apart the to clean it. Can dirt / malservice cause diode failure and leakback?

Jandh. Thanks, I will check the bottom tray. Did you have to replace the battery or did you seal the plug and top it off? On alternators, can you recommend a replacement and estimated cost?

[jandh]

I didn't think about fixxing the battery since it was still on warranty,  they didn't see the hole and i got a new one
Rare problem but it's nice to have info i guess eh?

[Vinman]

I had to chase down an ignition off draw on my 2003 Jeep.
In the process, I found out that an IOD of up tp 30 milli-amps is acceptable and expected. My Jeep was drawing 190 milli-amps with the ignition off.

To diagnose, I disconnected the positive battery cable and hooked a digital amp meter in line between the battery cable and the positve post to get a reading of 190 milli-amps.
I then proceeded to remove the fuses one by one until the draw changed. When I pulled the tuen signal fuse, the draw disappeared. In my case, it turned out the flasher I modified to eliminate the fast turn signal flash caused by the LED tail lights created the IOD.

There is also a fuse in the underhood fuse compartment labeled "IOD" which is not installed until the Jeep is PDI'd prior to delivery. That's why they can sit on the lot forever and still start.

Now with the 190 milli-amp draw, it would take almost 2 weeks to drain the deep cycle battery. Funny thing is it took me a couple fo years to even figure out I had a problem. I guess the Jeep never sat long enough to drain.

As far as the dirty alternator, hit it GOOD with a pressure washer for about 5 minutes until the water running out is clean. Before anyone says water is bad for the electronics please note that after every wheeling trip, I used to power wash the engine compartment and spent extra effort on the alternator, starter and belt driven accessories and with the exception of one idler pulley, I have never had to replace an belt driven component of starter.
 
Vince

[apex]

Thanks Vinman,

I'm thinking my voltmeter is broken because I can't get any milli-amp measurement using the method you described. I can measure DCV easily, but always getting 0's on DCmA.

Is there any serious problem running with the IOD out? Aside from the inconvenience of the radio/clock being reset every time. As far as I can tell it only resets the PCM  memory.

I know it isn't fixing the problem, but it might keep my Battery from dying every 3 days.

Tested DCV on battery without any connections 12.5V
Leads connected 12.24 DCV and falling
Running 14.25 DCV
With IOD out steady 12.5V

[Vinman]

Tested DCV on battery without any connections 12.5V
Leads connected 12.24 DCV and falling
Running 14.25 DCV
With IOD out steady 12.5V

If you're getting 12.5V with the IOD fuse removed and the engine running, the fuse removal also prevents the alternator from charging.

You can also use the test light as you said just remove the IOD fuse first. If you get a the light to come on with the fuse removed, you have a drain, pull the remaining fuses one by one until the light goes out.

The other thing to check is the battery, did you do load test? It could be as simple as a bad battery.

I have a load tester at home, if you need to check the battery, feel free to come on down to Cranston and i'll check it for you.

Vince

[apex]

Well, this would be an ongoing problem since '05. I've progressively bought better and better batteries. The Optima is now my third battery. This tells me there's a bigger problem at hand.

I suspect a combination of voltage regulator from the alternator and a 100-200 mA draw. The battery is just not getting enough voltage from the alternator and the mA draw is killing it softly.

The jeep won't even idle now. I have a portable jumper pack that I use to boost it, but I have to keep feathering the skinny pedal to keep it running.

Thanks for the offer on the load test. Might have to take you up on that sometime.

I friggin hate electrics!

[McClare]

If all else fails you can install a switch in your cab that turns off everything from your battery and just turn that off whenever you get out of the vehicle. That's a last resort though

[apex]

Yeah, I saw that at princess auto last week. thought it might be a last ditch band-aid fix.

Update, found a 70mA draw coming across fuse#1 - Park LPS & Skim.

Am I supposed to have park lights that come on when the Ebrake is engaged? I think rear brake lights are supposed to come on when the Ebrake is on.

I've got nothing coming on when the ebrake is engaged except for the dash light.

I'm thinking I found my short. At least I hope it is just the Ebrake, because I don't wanna f with the immobilizer.

Thanks everyone for you help. Almost got this figured out.

[Vinman]

Yeah, I saw that at princess auto last week. thought it might be a last ditch band-aid fix.

Update, found a 70mA draw coming across fuse#1 - Park LPS & Skim.

Am I supposed to have park lights that come on when the Ebrake is engaged? I think rear brake lights are supposed to come on when the Ebrake is on.

I've got nothing coming on when the ebrake is engaged except for the dash light.

I'm thinking I found my short. At least I hope it is just the Ebrake, because I don't wanna f with the immobilizer.

Thanks everyone for you help. Almost got this figured out.

You should not have any light other than the dash indicator light when the park brake is applied.

Now that you seem to have it narrowed down to a specific circuit do a further test. leave the fuse in and measure the drain as you pull the parking light bulbs one at a time. If you find a change in drain when you remove a  specific bulb, try replacing that bulb.
It wouldn't be the first time I've seen a fubared bulb that appeared to still work properly.

Vince

[apex]

Vinman, thanks for you help. Just to clarify, what do you mean by park light? in dash or on rear lights? Stupid question I know, but I just want clarity on what to test.

Tinkerer when you wrote...

"Is 70 mA enough to kill a battery in 3 days?  Shouldn't be for a reasonably charged battery, so yes you may have charge issues.  I have seen on a number of vehicles where excessive resistance in the wiring (bad connections etc.) caused an incomplete charge on the battery.  The charge circuit sees full voltage, but some of that voltage is lost across the bad connection and so the battery sees less.  (Yeah, Ohms law and I'm an electrogeek.)"

I had the exact same thought.  That low of a draw shouldn't kill my battery, not by a long shot. When you said I might be getting an incomplete charge, wouldn't that imply the alternator is faulty? Voltage regulator eh?  Considering this is my 3rd battery in 5 years, my guess is the Alt.

Thanks for the help Tinkerer. I'd definately appreciate a checklist. My largest ignorance not knowing what milli amps are expected across circuits. Maybe I am measuring an expected drop across the Park LPS / Skim circuit and figuring it I've found my problem.

Regardless, you've all been a great help thus far. I really do appreciate the help. Glad to see the club's members are still willing to help out a fellow jeep owner.