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Battery drains when parked over night

Tiny
MALLYBOY
  • MEMBER
  • 2008 MERCEDES BENZ GL450
  • 4.6L
  • V8
  • 4WD
  • AUTOMATIC
  • 102,567 MILES
This vehicle always drain battery after driving it all day and when parked at night and in the morning you will notice that it has drain the battery. What could be likely causes to this problem, is it a faulty module or components?
Monday, January 17th, 2022 AT 1:20 AM

13 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

It could be almost anything.

You need to remove the negative cable from the battery and use a voltmeter in line. Red lead to the cable and black lead to the battery post.

https://www.2carpros.com/articles/car-battery-dead-overnight

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Let it sit for 15 minutes for the modules to go to sleep. Then set the meter to DC amp and read the meter. It should be50-75 milliamps only. Any more than that, you will need to start pulling fuses one by one until the draw drops to normal. That will tell you the circuit that is causing the draw.

Let me know the results.

Roy

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Monday, January 17th, 2022 AT 1:49 AM
Tiny
MALLYBOY
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You need to remove the negative cable from the battery and use a voltmeter in line. Red lead to the cable and black lead to the battery post. I didn't understand it, use a picture to show me how place Red Lead to the cable and Black Lead to the battery post. Thanks for response.
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Monday, January 17th, 2022 AT 3:28 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Did you view the guide? It shows it in detail.

Remember, you are measuring current, not voltage.

I attached a youtube video for you.

https://www.youtube.com/watch?v=KF1gijj03_0

Roy

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Monday, January 17th, 2022 AT 3:35 PM
Tiny
MALLYBOY
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I do not understand the video, too much talking without showing how to set the multimeter to current scale and how to probe the multimeter lead to battery cable and negative lead to battery post, please show me with pictures how to set the multimeter to scale it will be used for the test and where to probe the positive lead of the multimeter and negative lead of the multimeter. Please
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Wednesday, January 19th, 2022 AT 12:48 AM
Tiny
ASEMASTER6371
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I will explain again.

Remove the negative cable. Take your voltmeter leads and attach the red lead to the negative cable end. Take the black lead and attach it to the negative battery post.

Set the voltmeter to DC amps and read the measurement.

Roy
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Wednesday, January 19th, 2022 AT 3:32 AM
Tiny
MALLYBOY
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Take the black lead and attach it to the negative battery post. Do you mean Negative battery terminal or Head?
Set the voltmeter to DC amps and read the measurement. Look at the picture below and see if I set the multimeter correctly
Image (Click to make bigger)
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Wednesday, January 19th, 2022 AT 7:52 AM
Tiny
ASEMASTER6371
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On the screen, does it say AC on the left side? Very blurry and hard to read.

Roy
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Wednesday, January 19th, 2022 AT 7:56 AM
Tiny
MALLYBOY
  • MEMBER
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On the screen, does it say AC on the left side? It says DC on the left side and mA on bottom right of the screen.
Let me update another picture
Check and know if I set the multimeter to the scale correctly?
Image (Click to make bigger)
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Thursday, January 20th, 2022 AT 11:36 PM
Tiny
ASEMASTER6371
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The dial is set correctly.

Now press the range button until you see AC show up on the screen.

Roy
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Friday, January 21st, 2022 AT 12:52 AM
Tiny
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Now press the range button until you see AC show up on the screen.
Has seen AC on the screen bottom left and V on bottom right of the screen.
What is the exact value that when it shows up, you will know it's good and the values that when it shows, you will know it's a problem?
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Friday, January 21st, 2022 AT 11:37 AM
Tiny
ASEMASTER6371
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50 to 75 milliamps.

Roy
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Saturday, January 22nd, 2022 AT 7:18 AM
Tiny
MALLYBOY
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50 to 75 milliamps. Okay, let me check and get back to you.
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Monday, January 24th, 2022 AT 12:12 AM
Tiny
ASEMASTER6371
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Sounds like a plan.

I will be here.

Roy
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Monday, January 24th, 2022 AT 3:12 AM

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