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2001 E46 330ci Red battery light.. then more came oon

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#1 · (Edited)
Went out for a drive, battery light flickered on yellow, then red then stayed on, decided to get home on the way home, 5 mins later.. dsc, brake, abs lights came on.. wipers slowed.. airbag light came on.. thenbrakes light went red.. indicators all but gave up.. managed to limp it onto the drive..

So I'm guessing the altanator has given up the ghost, what do you guys reckon? are they pretty easy to change? :frown
 
#6 ·
oooh just found video about testing alternatoe output using the on board diagnostics.. very clever.

so possible alternator, needs new rear diff bush and a leak in the coolant system somewhere.. great start to BMW life!. Guess at 80k miles to be expected!
 
#10 ·
Defo looks like Alternator, charged battery for pretty much 24hrs on charger/conditioner, charged fully in around 4-5hrs, Put it in the car, did Battery test on dash, showed a healthy 12.6, started car dropped to 12.2 and Battery/Alternator light came on...

Think i'll be ordering a new alternator!

Talking of which, which alternator? Bosch, Valeo or other?
 
#11 ·
I've got a similar problem with mine which I haven't fixed yet.

I read a few topics on it around the internet and from what I can see buying an aftermarket alternator didnt fix the problem but as soon as they got a genuine BMW one it went away. Somebody recommended getting one of a breakers and replacing the voltage regulator, apparently he's fixed a couple like that.

I got a new battery for mine 2-3 months ago and it was running fine until 2 weeks ago. I haven't driven it all weekend and when I tried to start it on monday to go to work it wouldnt and the OBC readout showed less than 10V on the battery (ridiculous). Anyway I charged the battery and when I started the car the alternator voltage readout was showing less than 13v!

How do i know it's the alternator though? Could it be a faulty part/wire that's eating up the voltage? I've also been having bad idling and errors about the O2 sensor and thermostat (O2 sensor has been changed), was wondering whether this can have anything to do with it.

Anyway let us know how you get on...
 
#12 ·
As others have suggested to me, I would check the earth strap and alternator leads, if there is a bad ground I'm guessing the charge may not get through due to resistance? also if it is a bad earth I'm guessing this could cause issues with power with the car running.

I have yet to do this but as the car suddenly had the charge light and all the power was getting lower it suggested to me the car was running just on the battery.. so I'm talking to other people they seem to think its my alternator.

I have heard of stories of something to do with the aircon sucking attery power on short trips and if left for a while.. I don't know the in and outs.

My Lotus had an Idle problem, when I cleaned up the engine earth strap + new battery the problem went away.

then again all I know about electrics is its sparky and makes your hair stand on end, and don't lick a 9v battery!
 
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