How do you diagnose a bad v regulator? When the lights are on I get only about 13-13.5 volts on the gauge, with the lights off I get 14. Thats ok, I know but i want to see what makes the drop stay.

 

no one?

 

What do you mean by diagnose? I think that you have already diagnosed that you have a bit of a screwey regualtor. The only thing you can do to fix it is to get a new alternator, since the regulator is built into the alt. Trust me I have the same problem only worse. When I start my car the altnator and regualtor don't kick in at all until I wake it up by revving the engin, then it will kick in.

 

I thought bosch units have a replaceable regulator. The valeo ones don't... I think mine is a Bosch unit

 

I am guessing at that rate it would be cheaper just to replace the whole unit. If you want I have an OEM 120 amp Bosch alternator. If you need it let me know.

I searched for car parts and I couldn't find a voltage regulator by itself for an audi.

 

This is a screenshot of the Bentley Manual's diagram of the Bosch alternator and voltage regulator:

[IMG]local://upfiles/18457/BEF749E66BD941CA94A0387861868B22.jpg[/IMG]