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Unread 10-25-2008, 07:53 PM   #1
feetdoc1
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1984 CJ7 
 
Join Date: Oct 2008
Location: Greenville, NC
Posts: 8
Mysterious Battery Drain?

New to the Jeep world, bought a 1984 cj7 258 4 spd.
All the gauges work inside to my amazement, lol.............
The only aftermarket items on the jeep are a winch and interior light wired to the headlight switch. Both were disconnected and still experiencing the drain.
The problem is that I have a drain on the battery somewhere, battery is dead within 1-2 days while parked.
Here is what I have done....please help
New battery and had the alternator checked at two seperate shops and was told it was in need of replacement. So I plan on removing and having it tested off the jeep tomorrow but in the mean time I need some direction.
Next disconnected the negative battery cable and connected a meter and removed fuses one at a time with no change in what appears to be a 3.6 amp draw on the system with ignition off, according to the local parts store computer.
What is causing this drain?
Before you guys tell me to search the site, I have spent the past week searching and reading this site and my Haynes repair manual with no results.
Could a bad alternator cause this or is there something else?
Thanks in advance!
I also apologize if there is some glaringly obvious that I have overlooked.

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Unread 10-25-2008, 08:12 PM   #2
74_jeep
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1974 CJ5 
 
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Location: Southeast Michigan, Michigan
Posts: 161
Could possibly be a diode stuck in the alternator. Disconnect the alt wire and see if it drains down .


I had this happen on a Ford F150 , turned out to be a relay that was bad from corrosion .

Good luck

Heres a good link :
http://www.inliners.org/tech/tech6.html
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Unread 10-25-2008, 08:39 PM   #3
64Jeeper
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1964 CJ5 
 
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Location: Spring City, Pa.
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Here is a good test.

With everything in the Jeep turned off, including the key switch

Disconnect the "Negative" battery terminal, and attach a 12V test light between the negative terminal, and the negative cable.

If the light lights, then yes, you have a drain.

Next, with the test light hooked up, start removing fuses in the fuse box until the light goes out. Once it does, that should tell you where your drain is.

I've never had an alternator drain a battery, and I'm not saying that it can't happen (not trying to on your toes 74Jeep), I'm just giving you a simple test to try before you just go out and buy an alternator.

Also, with the engine running, check the voltage on the battery. If it's not at least 13.5 or more, then your alternator isn't charging the battery, and it needs to be replaced.
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Unread 10-25-2008, 09:35 PM   #4
Fjguercio
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1978 CJ7 
 
Join Date: Dec 2007
Location: Burnsville, MN
Posts: 2,814
does your horn work. I have had the horn button on the steering wheel make contact and the relay energized would drain the battery. This would also have some resistance and not show as a total short.

Second Idea is to disconnect the Radio, the program wire, keeps a small amount of power to the radio to keep the programing. This is most likely not the short, small drain, but could keep you from finding the short when you are disconnecting fuses.

The last idea is you have a wire that has rubbed and shorted to the body ground somewhere.
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Unread 10-26-2008, 06:19 AM   #5
feetdoc1
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1984 CJ7 
 
Join Date: Oct 2008
Location: Greenville, NC
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Thanks for all the suggestions and here is where I am........
Test light does light with the negative terminal wire removed and using the test light to make contact with the negative wire.
Removed every fuse and still getting a drain with the test light as used above.
Horn works well so don't think there is a problem there either......
Also the PO installed an interior light mounted up on the windshield that is turned on with the headlight switch and rotating the switch until it clicks. Light will come on but noticed you get a very small voltage/shock(almost like someone pulling a hair out of your leg...lol) passing through when touching the switch and frame body at the same time. I dissconnected the headlight switch entirely and still getting this draw from the battery so I doubt thats it and the shocking sensation is only with the interior light on and grounding yourself to the frame.
I appreciate all the suggestions and will keep trying anything suggested...........just want to get out and play with this thing
Help
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Unread 10-26-2008, 10:36 AM   #6
64Jeeper
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Ok, if the light is still on after taking out all the fuses, leave the light in place, and remove the small wires from the alternator. If the light is still on, remove the large red wire from the alternator. If the light went out, then you probably do have a bad alternator.

You could also apply this same test to any electrical components that have been added by previous owners, or yourself.

Check any and all wires for rubbing, or pinching.

Hope you find it.
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Unread 10-26-2008, 12:15 PM   #7
feetdoc1
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Join Date: Oct 2008
Location: Greenville, NC
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New altenator on and test light is out......appears the alternator was causing the short
True test will be tomorrow to see if the battery is dead or not............keeping my fingers crossed
I will post an update in several days
Thanks again for all input
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Unread 10-28-2008, 08:15 PM   #8
feetdoc1
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Location: Greenville, NC
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Quick update battery drain issue resolved.
Alternator failed with resulting open diode or something which was draining the battery.
Replaced alternator and no more dead battery!
Thanks again for your suggestions.
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Unread 02-28-2009, 10:53 PM   #9
KurT5
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SORRY TO BRING UP A DEAD POST but i need to get back to college

I am having problems with keeping my jeep running (idle or at crusing speed not highway). Recently my battery has been low when i turn the key into the on position. After starting for the most part the battery gauge would rise to 14 and i never really had an issue. Now my jeep had a DEAD DEAD battery and when i jump start it it will only run for about 2 minutes before stalling out on me. I know that the injectors need about 10v to fire properly and i also know that my battery is about dead (9v). I do have aftermarket headlamps in the thing but i couldnt tell you waht they are because i bought them like that. I drove 2 hours home from college (no lights on) and then when i was at home i made a few trips that night and with the lights on. I was on my way home when suddenly my tach and speedo went out on me (straight to 0) and if i pushed my headlights off they sometimes came back. It started to buck and sputter like crazy so i rushed home and parked the thing (i never looked at the battery gauge because i was more focused on it not dying on the way back. This morning the battery is at 9v DEAD. I jumped it and it started up and as i disconnected the wires it ran for about 2 minutes and then suddenly died. I looked under the kick pannel from the steering wheel and looked for bare wires (this happened before and i hit it and it all came back) so i figured maybe a short or lose ground. I didnt do any volt meter testing but i looked for bare spots and nothing. I pushed all the connections tight and to my amazment some lights that never worked now worked. But again jump starting the jeep was fine but after the jumper cables were removed the car would die within minutes (both at idle and also crusing because it started to sputter and then cut off).

I did pull code: 41 Alternator field control circuit open or shorted
12 Memory standby power lost ( battery or comp recently disco)

I plan on removing the battery and getting a new one tomorrow and while its out i want to check the ground wires and such. After installing the new battery i plan on racing to autozone and having them test my alternator.

First i want to know if the stalling out issue is possible related to this
Second i want to kno how to set up the secondary relay switch that people talk about when installing aftermarket headlamps
Third does anyone out there that might have had this problem have any information that will help me get back to school tomorrow?
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Unread 03-01-2009, 12:11 AM   #10
SnowdogMarc
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Your vehicle will run of the alternator with no battery once it's started...if it's stalling out after a couple of minutes I have to say your alternator is pooched. Take it off and get it tested.
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Unread 03-01-2009, 06:12 AM   #11
halpeters
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Although SOME (not all) vehicles will run with the battery disconnected, this is a VERY bad thing to do. The Alternator does not make "smooth" 12 volts (actually 14.4volts). The power coming from the alternator is an an inverted sine wave - it goes from 0 volts to 14.4 volts many times a second. The battery is used to smooth this power and provide smooth DC power.

Without the battery connected, the power spikes from the alternator can damage electronics, and the alternator it self.....

Hal
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Unread 03-01-2009, 11:55 AM   #12
SnowdogMarc
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Quote:
Originally Posted by halpeters View Post
Although SOME (not all) vehicles will run with the battery disconnected, this is a VERY bad thing to do. The Alternator does not make "smooth" 12 volts (actually 14.4volts). The power coming from the alternator is an an inverted sine wave - it goes from 0 volts to 14.4 volts many times a second. The battery is used to smooth this power and provide smooth DC power.

Without the battery connected, the power spikes from the alternator can damage electronics, and the alternator it self.....

Hal
Good point but I never told him to disconnect his battery and try it. I simply said that if it's stalling out after he removes the jumper cables to the good battery his alternator is not outputting what it should. Put a volt meter on it and you should get 14 volts when the engine is running. If this is a newer battery it can take getting run flat once or twice and survive, if it's 4+ years old it's prob done for and you will need a new one. Take the alternator off and get it tested at Autozone or NAPA.
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Unread 03-19-2009, 07:53 AM   #13
Oily
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Quote:
Originally Posted by 64Jeeper View Post
Here is a good test.
With everything in the Jeep turned off, including the key switch disconnect the "Negative" battery terminal, and attach a 12V test light between the negative terminal, and the negative cable.
If the light lights, then yes, you have a drain.
Quote:
Originally Posted by feetdoc1 View Post
Test light does light with the negative terminal wire removed and using the test light to make contact with the negative wire.
How does this work ? What kind of test light ?
My test light clips to a known ground. The other end you probe for a hot wire/scource. When found, the light will illuminate.
How does going from the negative battery terminal (known ground) to the negative battery cable illuminate the test light ?
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Unread 03-19-2009, 08:00 AM   #14
Mike Romain
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Quote:
Originally Posted by Oily View Post
How does this work ? What kind of test light ?
My test light clips to a known ground. The other end you probe for a hot wire/scource. When found, the light will illuminate.
How does going from the negative battery terminal (known ground) to the negative battery cable illuminate the test light ?
You take the negative battery cable 'off' the terminal..... If the system is using power, the test light makes the connection between the cable and the tweminal and lights up.
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Unread 03-19-2009, 08:28 AM   #15
Oily
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Quote:
Originally Posted by Mike Romain View Post
You take the negative battery cable 'off' the terminal..... If the system is using power, the test light makes the connection between the cable and the tweminal and lights up.
Yes, I tried it (turned on my headlights) and saw it work.
Where did the positive current come from ?
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