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Battery Drain Issue

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  #1  
Old 10-16-2010, 11:15 AM
DustyLBottoms's Avatar
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Default Battery Drain Issue

1994 Disco. Battery goes dead after 2 days of not driving.

Did a draw test. Vehicle draws 4.83 amps while sitting. After disconnecting EVERY fuse the only one that would affect the draw was the 100amp Alternator fuse. When disconnected it only accounted for .83 amps. Leaving a 4 amp draw that I can't figure out for the life of me.

Now, it seems the previous owner had tied in some brush bar lights. I've removed all the crappy wiring I can find from those. Could there still be a hot draw from them? Is there unfused 12v somewhere that I'm missing!?

Please see the pics below.

Mess of wiring under the front passenger seat, what is this for?

http://www.flickr.com/photos/37974521@N03/5086214359/http://www.flickr.com/photos/37974521@N03/5086214359/ by http://www.flickr.com/people/37974521@N03/, on Flickr


Wires that come from under the drivers seat & center console:

http://www.flickr.com/photos/37974521@N03/5086811516/http://www.flickr.com/photos/37974521@N03/5086811516/ by http://www.flickr.com/people/37974521@N03/, on Flickr



Close up of wires from above:

http://www.flickr.com/photos/37974521@N03/5086218645/http://www.flickr.com/photos/37974521@N03/5086218645/ by http://www.flickr.com/people/37974521@N03/, on Flickr
 
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Old 10-16-2010, 01:30 PM
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Under the passenger seat was a CD changer.

Thats all I have, sorry.
 
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Old 10-16-2010, 02:11 PM
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The fuses you pulled while checking drain, did you include both the under hood fuse box and the under dash fuse box?

4.8 amps will definitely drain a battery in 2 days. You need to get that drain reduced to a few millamps to fix this problem.
 
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Old 10-16-2010, 02:19 PM
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Originally Posted by lordmorpheus
The fuses you pulled while checking drain, did you include both the under hood fuse box and the under dash fuse box?

4.8 amps will definitely drain a battery in 2 days. You need to get that drain reduced to a few millamps to fix this problem.
Yes, both fuse boxes, including all the HD fuses & the 7.5 amp fuse for the code output under the passenger seat.
 
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Old 10-16-2010, 02:29 PM
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Hmm. If NONE of the fuses, when removed, killed that 4+ amp drain... I would start looking for non factory wire splices. Do you have any extra wires on your positive battery cable? That's the only thing that comes to mind. If the previous owner tapped into some factory equipped wire, that wire should be on a fused circuit, and killed when the fuse is pulled. A direct connection to the battery, unfused, is all I can think of.
 
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Old 10-17-2010, 01:44 PM
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Originally Posted by lordmorpheus
Hmm. If NONE of the fuses, when removed, killed that 4+ amp drain... I would start looking for non factory wire splices. Do you have any extra wires on your positive battery cable? That's the only thing that comes to mind. If the previous owner tapped into some factory equipped wire, that wire should be on a fused circuit, and killed when the fuse is pulled. A direct connection to the battery, unfused, is all I can think of.
That's kinda what I'm thinking. However, positive battery cable shows no splices. I'm thinking that the splice must be in the dash somewhere, I currently have it pulled apart looking.......
 
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Old 10-17-2010, 03:43 PM
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I would also look at the wiring associated with the alternator. PO may have tied a wire into the positive side of the alternator for some dumb reason. That may account for it being associated with the alternator fuse.

There are a lot of factory splices in the factory wiring bundles both under the carpets and around the drivers seat and center console. Isn't the cigar lighter hot all the time or is it wired thru the key?

You may have some leakage going on with the factory splices if the carpets got very wet and things corroded. I would go ahead and yank the carpets as well.
 
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Old 10-17-2010, 06:38 PM
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Ok! Check it out, I didn't find this before because you have to have TWO fuses pulled at the same time to lose the draw!? Watch the video I made.

Edit: Meant to say "AMPS" in the video, not volts.

http://www.youtube.com/watch?v=68Ed44KlVuE
 

Last edited by DustyLBottoms; 10-17-2010 at 06:53 PM.
  #9  
Old 10-17-2010, 09:22 PM
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Looks like you have the fun job of getting a wiring diagram, then tracing wires back from the fuse block to see where the problem is. You might see where the two circuits are joined, or start disconnecting things on each circuit to see when the drain disappears.
 
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Old 10-19-2010, 07:33 AM
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Haven't figured out the draw yet. Me and two other friends (we all work at an LR dealership) have been pulling our hair out on this one. last night we followed the diagrams and spent an hour doing pinpoint tests and have hopefully isolated it to a point in the wiring harness where the Alternator lead & the wiring to the ECM are routed together. Now I'll split the harness open and see what I can find.
 


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