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Discussion Starter · #1 ·
I had the alternator replaced TWICE yesterday and still having problems....

I had replaced it only because it was making one heck of a noise.. (bearings went out)... So I took it in and had it replaced today with a 80 amp BOSH alternator. It was charging and checked out ok so I drove home. I made a quick stop (about 20 min) at the store and when I came out and started it up, the Battery light was on..
So I took it back and they changed out the Alternator with another new one, tested it, yep charging.. So i went home again.. came out tonight about 5 hr later, and the Battery light is on again... It's not charging...

What is going on...?? The battery is 2 years old and the only reason for changing the Alternator was because of the bearing noise... Belt is new, Idler pulley is new, engine is quiet at idle.

Any ideas..?? I am stuck until Monday unless I can fix this...

'96 328i e36

Thank you
Dave
 

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Discussion Starter · #3 ·
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The one that was removed was the Original from BMW. Or at least it had all the BMW logo stamped on it, and looked old..
The one removed was doing fine (as far as I know) charging.. It was replaced because of the bearing noise was so bad...
The two new ones were from BOSH.. listed as 'OEM' BOSH for BMW...

Dave.
 

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Regardless of what it said on the alt, it was made by either Valeo or Bosch. My 1996 328i came from the factory with a Valeo. I have read that the unit MUST be replaced with one from the same manufacturer, but I don't know how much truth there is to this :dunno
 

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Discussion Starter · #5 ·
I went back today to the BMW Mechanic, Since I had left him a message last Thursday (new years eve) I was happy to receive a call a few min. before 8:00am. He sounded concerned and wanted me to bring it in after traffic eased up.

I got it to the shop with no issue other then my hands being very cold seeing that I had to keep the rear window slightly open and the sun roof vent open to circulate some air to keep the windows from fogging up.

He tested it and sure enough it wasn't charging. He had already had another alternator ready. He put something across the ' + ' and ' - ' bolts on the alternator then it started charging again. Battery light went out.

He told me that the 'switch' that tells the alternator to charge or not charge had got stuck in the off or not charging... ( I'm sure it's more detailed then that, but he but it in basic terms for me..)

So he still had my old alt. and check it out to, other then the bearings being bad it was charging fine. So he replace the Bosch alternator with the other one that had arrived this morning. He told me that he had it checked out before it was delivered. He installed it, ran some checks and looks ok.. 14.53v charging and with accessories on 13.79v... If my memory is correct.. :confused:

So,.. I drove around in the rain and cold with as many accessories on as I could turned on. Wipers, lights, radio, charging my iPhone, seat heaters, rear window defrost, and heat for about 30 -45 min then came appon a mall and parked it, turned it off and let it sit for about 20 min while I went shopping for some thing for the wife (didn't find anything)... So I returned to the 328i I started it up,.. No issue so far... As before by this time I would be staring at the bright red Battery Icon on the dash wondering what is going on...

So I am home now and will let it sit again for about 2 hr. before I must go get some work done. 1:30pm
 

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Sounds like a bad voltage regulator or charging diode. I'm glad to hear it is going well so far.
 
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