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Battery goes dead after a week or so of sitting

Cadiman1949

Nubee to Jeeps
Supporting Member
Jan 6, 2019
11
Albuquerque, NM
Hello all, I am new to Jeep TJ's and hope there is someone out there that can help me with an issue I am having with my recently acquired 2006 Rubicon TJ.

To start off I will let you all know that I am a very experienced mechanic but have been working on Hot rods and 50's/60's Chevy's for the last 18 years... I have a lot of electrical experience so you can talk technical with me... but it's been a while since I have done much on modern cars and why I hoping to find a little help here.

First: I had noticed that when the Jeep sat for 3 or 4 days that the engine cranked noticeably slower than it did after I drove it for a while. I checked alternator output voltage and found it running 13.8 to 13.9v... a little low but still enough to charge the battery. one day after the Jeep had sat about a week or so I went to start it and got just the old click-click-click of a very low batter that could not engage the starter.... two minutes on a shop battery charger and she cranked right up.

Second: I replaced the battery... I knew nothing about the battery other than it was a heavy duty "Die Hard" and it had a 2015 date code on it and the battery terminals had some green buildup on them. I had cleaned the sulfate off the battery posts, terminals and cables. I installed a battery disconnect on the negative cable (something I do on almost all of the old cars I work on). I checked the jeep ever few days to be sure it would start and noted the alternator output. (BTW the alternator output went to 14.0v). I thought the problem was solved with the new battery and a better alternator voltage output until 3 days ago. The Jeep had sat for 10 days untouched when I went to start it... you guessed it... click-click-click.

What I did next:

Charged the battery to 100% with an automatic battery charger
Installed an ammeter inline with the negative battery cable

Checked battery draw and noted the following:
1 amp for about 1 second when the connection through the ammeter was initially made and then .5 amp steady.
.5 amp withy hood light on, I unplugged the hood light and the draw went to down to .3 amps
I unplugged the 2 wire connector at the back of the alternator (no change)
I took the main battery wire from the alternator to the battery (no change)

I started pulling the fuses under the hood and noted the following:
The 10 amp "Acc 2" fuse and the draw dropped to less than .05 amp (the draw you expect to see with an ECM and radio memory).

I do not have a wiring diagram for this Jeep so I am asking for some help.

Addition bits of information. I noticed that the Acc 2 fuse powers up the under-hood light. Also, my jeep came to me with half doors and the interior lights do no come on when the doors are opened. It has door jam switches but they do not activate the interior lights when the doors are opened. The interior lights come on for about 10 or 15 seconds when you turn the ignition switch off and you can manually turn them on using the dimmer function for the dash lights on the headlight switch.

I will be posting additional threads for a Code PO440 which only comes on when the fuel tank is below 3/4 full
 

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
10,958
Escondido California
Did the previous owner install a burglar alarm or external audio amplifier? Those are often installed incorrectly so there's a continuous power draw. Any relays anywhere that a previous owner installed, like perhaps for driving lights? They can be miswired too so they are off when the driving lights are on but have to be turned on to shut the driving lights off due to some relays having both normally-open and normally-closed contacts.

Also, once you figure out what's draining the battery, I would not leave the battery's negative (or positive) lead disconnected when you're not driving it. That will eventually erase the computer's adaptive 'learned' memory and the engine may not run right for a while after first being started. Better to keep a small battery maintainer connected to the battery when you're not driving it, that's why my 10 year old Sears Diehard Platinum is still in good condition.
 
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Cadiman1949

Cadiman1949

Nubee to Jeeps
Supporting Member
Jan 6, 2019
11
Albuquerque, NM
Did the previous owner install a burglar alarm or external audio amplifier? Those are often installed incorrectly so there's a continuous power draw. Any relays anywhere that a previous owner installed, like perhaps for driving lights? They can be miswired too so they are off when the driving lights are on but have to be turned on to shut the driving lights off due to some relays having both normally-open and normally-closed contacts.

Also, once you figure out what's draining the battery, I would not leave the battery's negative (or positive) lead disconnected when you're not driving it. That will eventually erase the computer's adaptive 'learned' memory and the engine may not run right for a while after first being started. Better to keep a small battery maintainer connected to the battery when you're not driving it, that's why my 10 year old Sears Diehard Platinum is still in good condition.
Hello Jerry,

One of the very first things I did was pull the seats, carpets, glove box and dash bezels out of this Jeep. All kinds of wiring had been fooled with. I removed an aftermarket radio and replaced it with a rebuilt factory 6-Disc Stereo. The center console was removed and the wiring all through there was checked. There was a relay buss installed under the hood with lots of wiring installed that went no where (lost of stuff removed by previous owner). I removed all of this wiring and wired the buss so that it get powered up with the key on and installed all of the exterior lighting on the jeep myself. Every place I found butt-connectors I removed them and soldered the connections and heat-shrinked. I spent a full week going through and getting rid of all the wiring that was there and unused.

I know that my .3 amp draw is coming from the Acc 2 fused circuit. I know the door jam switches do not work the interior lights. Everything else work perfectly.

If I drove this Jeep every day or even once or twice a week I'd have never noticed the problem. With the new battery it takes 8 to 10 days for the battery to get too low to start the vehicle where it took about 5 or 6 days with the old battery.

If I had access to what is all on the Acc 2 fuse circuit I could trace this problem down fairly easily. I fear I missed something when I went through all the wiring stuff done by the previous owner/owners. I do not know why the door jam switches do not turn on the interior lights and suspect this could be my issue. Is there a way to disable these switches on a Jeep if you choose to run it without doors?

I will add a battery maintainer and only use my cut-out switch to disconnect the battery quickly when working on the electrical on the Jeep. I always disconnect the battery when I solder on the wiring as well... just because it's what I have always done when working on computerized cars.

I understand wiring pretty well and just finished building a complete custom wiring harness for my 1988 Pontiac Fiero that I converted to a Tuned Port Injected 5.7l V-8 from a 1992 Camaro IROC-Z.

Do you have any access to Info for what the Acc 2 fuse circuit goes in the fuse block under the hood?

Thanks, Rick

PS, here's a couple pictures of my Fiero Project

20181219_143332_resized_1.jpg
20181219_143320_resized_1.jpg
20181219_143349_resized_1.jpg

20181219_143403_resized_1.jpg
 
Oct 12, 2018
92
Carnegie Pa
My bosses jeep did that too. He didn't have any extra lighting or aftermarket stereo. It was a completely stock Rubicon. Dodge told him that happened because of the stereo draw and the computer draw. We both never believed Dodges explanation. He put on a trickle charge when he knew he wasn't going to drive it for a week or so.
 

SOMD-JeepFan

Member
Nov 6, 2018
58
Hollywood, MD
Nice Fiero. I always wanted one. Maybe one day I will pick one up. I recently purchased my Jeep and I've noticed that my dome light does not come on when the doors are opened. I'm planning on waiting until the Spring before I start working on my Jeep. I'm thinking that the switch is being bypassed, so the doors can be taken off and not have the light stay on. Good luck with your Jeep.
 

John Scoggins

TJ Enthusiast
Oct 23, 2018
241
Houston, TX
I recently purchased my Jeep and I've noticed that my dome light does not come on when the doors are opened.
Check to see if there is a fuse in location 4, that is the dome lamp override fuse. When there is a fuse the dome lights will work with the door switch, if the fuse is removed then the light will not work (so that with the doors off the dome light will not stay on an run the battery down). Also the headlamp on warning will not work unless the #4 fuse is present.
 
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Cadiman1949

Cadiman1949

Nubee to Jeeps
Supporting Member
Jan 6, 2019
11
Albuquerque, NM
Check to see if there is a fuse in location 4, that is the dome lamp override fuse. When there is a fuse the dome lights will work with the door switch, if the fuse is removed then the light will not work (so that with the doors off the dome light will not stay on an run the battery down). Also the headlamp on warning will not work unless the #4 fuse is present.

Great Info! Thanks!!!
 

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
10,958
Escondido California
and only use my cut-out switch to disconnect the battery quickly when working on the electrical on the Jeep. I always disconnect the battery when I solder on the wiring as well... just because it's what I have always done when working on computerized cars.
I retired out of the technical side of the electronics and electrical industry where I spent my first 40 years of working. Disconnecting the battery while soldering or even welding is actually doing the complete opposite of what you heard it does... disconnecting the battery is actually removing highly protective electrical filter. Not only is it a battery, it also performs as a huge filter capacitor. That means it absorbs and 'filters' any electrical spikes/noises out while doing things like soldering or even welding. Disconnecting the battery during such operations would be removing a big protection.

Disconnecting the power/battery makes sense when doing things like adding new wiring, splicing, installing connectors, installing new devices like outlets, etc. but I'd consider leaving it in whenever doing anything that could produce an electric spike, noise, etc.

In fact I did a little more welding on my TJ over the weekend (reinforcing the roll cage) and I left the battery connected to help protect my TJ's ham & CB radios, audio system, computer, etc. while welding. The battery really does have a protective role in addition to being a source of power. As said above, it makes a great filter capacitor in addition to being a source of power. :)
 
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Cadiman1949

Cadiman1949

Nubee to Jeeps
Supporting Member
Jan 6, 2019
11
Albuquerque, NM
I was able to get a wiring schematic of the #26 fuse "Access 2" and traced the problem to my compass mirror. It is not the original one and for some reason it is causing a 250ma draw on the battery. I unplugged the wires from the back of the mirror and POOOOF the draw is gone. Problem solved I just need a factory mirror with a built in compass. Thanks for all the pointers you all!!! I'm sure I'll like being a member of this community.