V6 (1994-2004) Mustangs Technical discussions on the 3.8L and 3.9L V6 torque monsters

Parasitic battery drain

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Old 10-29-2017, 09:15 PM
  #1  
ranger90
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Default Parasitic battery drain

Hello,

2000 base model.. 3.8L V6, auto trans.

I've been fighting a dead battery in my car since I bought it. I had it at my brother's for repainting, and just got it back.

I was drawing 0.15 amps (on the 10A scale) before I pulled a 40A fuse in the power block under the hood. The owner's manual says "Instrument Cluster, PCM"

What do I look for next?

Thanks in advance.
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Old 10-29-2017, 09:54 PM
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imp
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Originally Posted by ranger90
Hello,

2000 base model.. 3.8L V6, auto trans.

I've been fighting a dead battery in my car since I bought it. I had it at my brother's for repainting, and just got it back.

I was drawing 0.15 amps (on the 10A scale) before I pulled a 40A fuse in the power block under the hood. The owner's manual says "Instrument Cluster, PCM"

What do I look for next?

Thanks in advance.
Digital voltmeter/ammeter? Can't read 0.15 amps on a 10 amp analog scale. .15 is way too high. The several memories kept alive, PCM and airbags, shouldn't be much over 1/10 that amount, maybe .025 amp. 25 milliamps. What effect did the fuse removal have on the current drain? imp
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Old 10-29-2017, 11:23 PM
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ranger90
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Originally Posted by imp
Digital voltmeter/ammeter? Can't read 0.15 amps on a 10 amp analog scale. .15 is way too high. The several memories kept alive, PCM and airbags, shouldn't be much over 1/10 that amount, maybe .025 amp. 25 milliamps. What effect did the fuse removal have on the current drain? imp
Yes. I was using a digital multi-meter.

I agree. 0.15 is still too high.

When I pulled the fuse for the "Instrument Cluster, PCM" the Digital Ammeter dropped to zero. I switched to the milliamp scale and got about 20-25 (If Memory serves.)
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Old 04-08-2020, 06:16 PM
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I'm having the exact same problem in my 03 GT. Digital meter is reading .18 Amps at the same fuse with the keys out of the ignition. Any insight on the probable cause is appreciated.
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