BMW 3-Series E46 (1998 - 2005) - 03 1.9 Alternator charging light

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Tue 26 May 2009 21:53
03 1.9 Alternator charging light - Richie_green
I have purchased a 3 Series and have noticed an intermittent issue when changing gear and the red light flashing on, its the engine light (in the middle with a battery. Then tonight on the way home from work, the seemed to loose power when pulling away and just died. It started up straight away - I called the garage but cant get it in till next week.

Any ideas on a possible problem?

Edited by Pugugly on 26/05/2009 at 22:49

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Wed 27 May 2009 14:45
03 1.9 Alternator charging light - buzbee
Does the car have a rev counter and if so, what are the revs when you de-clutch without your foot on the accelerator?

If the revs are too low, the alternator produces a low voltage, and the light come on. Similar to when the engine is not running but the ignition is switched on.

In that case the red light problem is caused by a low tick-over condition.
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Wed 27 May 2009 16:39
03 1.9 Alternator charging light - Richie_green
No the light only comes on intermittantly when driving normally changing gear. It flashes on then goes off when the vehicvle is engaged into gear. Also, the car seems to 'surge' sometimes and the revs either drop/increase - would this be the same issue.

The garage have said it may be the alternator but they need to keep it.

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Wed 27 May 2009 20:14
03 1.9 Alternator charging light - zookeeper
i'l take 5/4 fav its the alternator
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Thu 28 May 2009 16:24
03 1.9 Alternator charging light - Richie_green
Just picked up the car and they cant find anything wrong with it. They have had 4 people out in it and nothing happened. He has suggsted I keep it for a week and make a note of it.

Its happened again already - the car was in second gear at quite high revs and the alternator light flashed on and the revs jumped down from 4000 to 3000. The garage have checked the alternator and said its fine.
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Thu 28 May 2009 18:19
03 1.9 Alternator charging light - Pugugly
Did the actual engine revolutions jump or was it just the rev counter ?
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Thu 28 May 2009 22:18
03 1.9 Alternator charging light - Richie_green
Just the rev counter
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Mon 24 Aug 2009 14:05
03 1.9 Alternator charging light - Gormless Bleeder
Have a similar issue . Battery light comes on fro a split second and is associated with a drop in Revs.

Ran the car with a voltmeter on for a while and could see the discernable drop in voltage output

Asked a trusted garage to check Alternatior , Drive belt and battery - all are fine. I have followed this up with a visual check of my own - thats fine too


Lokking at the charging system wiring diagram, the alternatior feeds batterery power to the battery via the starter motor - The immobiliser hangs off that and i have a sneaky suspicion about it, becuase the alarm has been going off recently too. Other than that , im scratching my head too
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