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7 Series - E38 (1995 - 2001)

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  #1  
Old 07-01-2012, 06:29 PM
Bmwsport325 Bmwsport325 is offline
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Mein Auto: 04 325i Sport
Battery Light on instrument cluster will not go away

I have a 2001 740i sport and I recently replaced the alternator and the battery. After replacing both, the battery light on the instrument cluster still stays on. Has anyone come across this issue before? Does the instrument cluster have to be reset?

Much Appreciated.
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  #2  
Old 07-01-2012, 09:21 PM
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joyism5 joyism5 is offline
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There was a thread not too long ago http://www.bimmerfest.com/forums/sho...hlight=battery
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Old 07-01-2012, 11:41 PM
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bluebee bluebee is offline
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Dunno if the E39 bestlinks will help you but this thread has everything we (collectively) know about testing the BMW battery and alternator ...

- DIY how to test a BMW E39 battery & alternator
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See also: E39 Bestlinks & How to easily find what you need
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Old 07-02-2012, 04:46 PM
Bmwsport325 Bmwsport325 is offline
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Thanks for the replies, when I start the car the alternator charges for about 3 minutes and then does not charge anymore and the battery light comes back on and battery gets discharged. Charging is around 11.5 V so its running battery.
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Old 07-02-2012, 09:57 PM
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joyism5 joyism5 is offline
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Quote:
Originally Posted by Bmwsport325 View Post
Thanks for the replies, when I start the car the alternator charges for about 3 minutes and then does not charge anymore and the battery light comes back on and battery gets discharged. Charging is around 11.5 V so its running battery.
You replace the alternator with a used one? What about the battery? Does it have at least 110A reserve capacity? Not CCA.

If is charging for 3 minutes only, the voltage regulator might be bad. Unfortunately, the liquid cooled alternator cannot be repaired, rebuild only by BOSCH approved technicians. When I was shopping for an alternator the best deal that I found it was at NAPA. Good Luck!
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Last edited by joyism5; 07-02-2012 at 09:59 PM.
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  #6  
Old 07-02-2012, 10:52 PM
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bluebee bluebee is offline
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Quote:
Originally Posted by joyism5 View Post
rebuild only by BOSCH approved technicians
There are a bunch of alternator rebuild threads in the E39 bestlinks ... e.g.,

- How to test (1) & determine exactly what alternator you have (1) & why rebuilding an alternator is preferable to replacing (1) & cn90 DIYs for rebuilding a 1998 air-cooled BMW Bosch alternator (1) (2) or his VW Bosch alternator (1) & cdawg246's quest for materials for a Bosch water cooled alternator rebuild (1) & Aioros' 1999 Valeo Alternator rebuild DIY (1) and his quest for materials (1) & Cn90's explanation of where to get hard-to-get alternator rebuild parts (1) & how to tell from the part number if a replacement alternator is actually rebuilt "by" Bosch (1) & a DIY for replacing the brushes in an (Audi) Valeo alternator (1) & a Bosch alternator bearing replacement from a 1997 MB S600 (1) & from a Range Rover (1).
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See also: E39 Bestlinks & How to easily find what you need
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