2000 Mustang 3.8L battery drain

Jl74526

New Member
Jan 24, 2019
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I did a drain test found out fuse number 6 in my engine compartment box 40 AMP It’s the instrument cluster, pcm. This has current when key is off Do you know if this is supposed to have current. And how would I find out if it is the PCM or something is shorted in my cluster? Thank you
 
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brucelee

New Member
Feb 25, 2019
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nc
hello, I'm having same trouble, I've noticed the theft light flashes when the switch is off. could this cause my energy loss. and if it is, how do I fix it? would appreciate any suggestion. thanks; brucelee
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
hello, I'm having same trouble, I've noticed the theft light flashes when the switch is off. could this cause my energy loss. and if it is, how do I fix it? would appreciate any suggestion. thanks; brucelee
i think this is the wrong forum for this but let me help you out, the theft light should flash with the key off. Have you checked the condition of your battery?
i'll move this for ya'll.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,368
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Houston Texas
IMO the problem is unlikely to be in a fuse out of the the battery junction box (BJB). The BJB is full of "always on" circuits that feed other circuits. Your time is better spent looking at the Central Junction box (CJB).

1999-2004 MY fuse panel schedule:
https://www.allfordmustangs.com/forums/4-6l-tech/305933-1999-mustang-gt-2001-motor-swap-wont-fire-please-help.html#post2669271

Here's some information on how to perform a "voltage drop" test. Use the voltage drop method to "infer" the current through each CJB=F2 fuse by measuring the voltage drop across each fuse. The amount of voltage drop is less for larger fuses. There are tables for this. With everything off record the voltage drop across each CJB fuse. Use the fuse number scheme in the fuse panel schedule. Once the fuse is known the next step is to follow down what the fuse supplies.

Howto perform charging system voltage drop test
https://www.stangnet.com/mustang-forums/resources/howto-perform-charging-system-voltage-drop-test.56/

Note, if looking for an educated guess look first at the radio and/or the amp.
 

Markmustang4.0

New Member
Mar 24, 2017
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I have the same problem,I found a ground wire that is bolted to the fuse box under dash,it is a ground for my stereo sub woofer,factory system.i have not found a fix yet..since I unbolted it,my battery no longer drains out over night.