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Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 7 Series / 8 Series > 7 Series - E38 (1995 - 2001)

7 Series - E38 (1995 - 2001)

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  #1  
Old 08-11-2012, 11:59 AM
tresk tresk is offline
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Location: Phoenix
 
Join Date: Aug 2011
Posts: 23
Mein Auto: 2001 BMW 740iL
all of a sudden - no power anywhere

Just like the title says. Got in my car:
  • the dash computer wouldn't come on
  • No door lights
  • Not a single noise when I turn the key in the ignition
  • No headlights
  • No break lights
  • No inner lights
  • Key fob does nothing

No nothing.

I drive this car maybe once or twice a week. Nothing looked weird last time I drove it. The only thing was the air wasn't blowing too strong but nothing out of the ordinary. Don't think it is related.

I have a voltmeter. I checked the battery and I see 12V.

Where do I start troubleshooting?
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  #2  
Old 08-11-2012, 12:33 PM
tresk tresk is offline
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Location: Phoenix
 
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Mein Auto: 2001 BMW 740iL
UPDATE: I messed up while using my voltmeter. The battery actually reads about 2 volts. Something must have drained it completely. It's a relatively new battery. What's the best course of action? Get a battery charger? Replace it completely? Jump the car and drive around hope that it charges?
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  #3  
Old 08-11-2012, 01:35 PM
tresk tresk is offline
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Location: Phoenix
 
Join Date: Aug 2011
Posts: 23
Mein Auto: 2001 BMW 740iL
I just ordered a battery tender jr from Amazon. Hopefully this will be my solution. Anything I should watch out for?
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  #4  
Old 08-11-2012, 01:58 PM
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joyism5 joyism5 is offline
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Location: USA
 
Join Date: Jan 2011
Posts: 1,270
Mein Auto: '99 740IL, K75RT
The E38 (and not only) is known for battery drain issues. Could be several things, like alternator, amplifier, navigation, general module, and the list goes on. Nice DIY: http://www.meeknet.co.uk/E38/E38_Battery_Drain.htm
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  #5  
Old 08-11-2012, 02:48 PM
setconstr setconstr is offline
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Location: los angeles
 
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Posts: 417
Mein Auto: 2001 740i sport 2006 m6
re

Take the Battery out and have a slow charge put on it see what happens after that !
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  #6  
Old 08-11-2012, 07:48 PM
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bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,297
Mein Auto: 02 BMW 525i M54 auto 130K
Written for the E39, but it contains extensive information on how to test the battery & alternator which should apply as well to the E38:
- DIY how to test a BMW E39 battery & alternator
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Please read the suggested threads, where the best always add value to those threads, either by pictures or by descriptions, so the next person with the same problem stands on your shoulders.
See also: E39 Bestlinks & How to easily find what you need
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  #7  
Old 08-11-2012, 08:47 PM
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BMWFatherFigure BMWFatherFigure is offline
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Location: Perth, Western Australia
 
Join Date: Aug 2012
Posts: 2,370
Mein Auto: E23;E30;E38;E32;E34 +
When you use a battery minder or floating charger you may find it sets off the alarm all the time. I can explain why, just take my word for it. As for discharge other posts seem to have covered it..
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  #8  
Old 08-12-2012, 08:44 PM
tresk tresk is offline
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Location: Phoenix
 
Join Date: Aug 2011
Posts: 23
Mein Auto: 2001 BMW 740iL
My battery tender jr will arrive tomorrow. How long would it take to charge assuming it is fully drained?
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  #9  
Old 08-14-2012, 12:55 PM
tresk tresk is offline
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Location: Phoenix
 
Join Date: Aug 2011
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Mein Auto: 2001 BMW 740iL
Hey guys,

So I hooked up the Battery Tender Jr but I feel like it's not charging at all. Red light keeps blinking (it's been 16 hours or so). In the manual it says this may happen if the voltage is less than 3Volts. Does this mean it will never charge it or do I have to wait extra long because voltage was so low?
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  #10  
Old 08-14-2012, 01:52 PM
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BMWFatherFigure BMWFatherFigure is offline
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Location: Perth, Western Australia
 
Join Date: Aug 2012
Posts: 2,370
Mein Auto: E23;E30;E38;E32;E34 +
Use a standard charger to 'get things going' then revert to the floating charger Worked for me.
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  #11  
Old 08-20-2012, 09:33 PM
tresk tresk is offline
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Location: Phoenix
 
Join Date: Aug 2011
Posts: 23
Mein Auto: 2001 BMW 740iL
I ended up taking the battery to AutoZone. They tested the battery and said it was charging fine but it was closing time so they kicked me out. Once I took the battery home Battery Tender Jr started showing a solid red light instead of blinking so that was good. After a full day of charging it was still solid red but I decided to give it a try anyways. Engine turned the first try and everything seems to work fine. Drove the car all weekend w/o connecting to charger and still works.
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  #12  
Old 08-21-2012, 01:57 AM
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BMWFatherFigure BMWFatherFigure is offline
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Location: Perth, Western Australia
 
Join Date: Aug 2012
Posts: 2,370
Mein Auto: E23;E30;E38;E32;E34 +
Keep using the Bat Tender all the time. i suspect the battery is well under 'par' at the moment..
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