Battery light on in Audi B5. regulator or alternator?

Hi all.


My audi b5 suddenly showed the battery light in the dash.
After just making it home where I charged the battery, it gave well over 13 volt. With car running it goes under 13v and goes down fast.


Hoe can I check if its regulator?


Thanks!

On a BHW the charging wire goes directly from the alternator to the battery. The regulator is integral with the alternator and you need a new one.

I just took out the alternator. Quite Simple job.
You can just take of the regulator from the alternator. No problem. 4 screws and 2 bolts. The diodebridge comes of quite easy too. Just unclamp the 6 wires.
Which i did together with some local who knows about these things. He measured ther esistance of the diodes. Which was good so diodes are good. Alternator bearings sounded very good. Brushslide rings looked used but good.
So it must be the regulator. The brushes are uneven and very worn.
For the 25 euro i will try that over a swap or rebuild alternator.

A you say bhw. I have an AJM. The 1.9 tdi 85kw. These have the bosch alternator. 90 or 110amp i think.

Scubanero said:

On a BHW the charging wire goes directly from the alternator to the battery. The regulator is integral with the alternator and you need a new one.

Click to expand...

Actually on the Valeo, you can remove the back cover and replace the regulator or even the brushes.


.

The man checked the bearings, cleaned it all, put it back together.
I got a new regulator, which is one part with the brushes. Put it back together and it gives over 14 volt again.
The part costed me 20 euro.

Taking the alternator out, I had no idea what I would find. So took me just over an hour.
But put it all back with the mrs's watching and waiting in 20 minutes.
Very easy job! No speacial tools. Everyone could do this.
Never pay hundreds of euros/dollars at a garage for this!