I have read countless alternator threads and have not seen anything similar to what I have been experiencing on mine. Hopefully I can get some help to point me in the right direction. Here goes:

The vehicle has 220,000kms on it. Not sure if its the original alternator as I just picked it up about a month a go from a dealer with no history on it. Alternator lights intermittently comes on 1-2 times a week. I have been able when the light is on, check the voltage on the vehicle with my fluke dvm, measuring at the block in the engine compartment. It is showing 14.2v and when the ac kicks in a drop to 13.2 then comes back up to about 13.6 until it shuts off then back up to 14.2v. To me this is normal. As my wife drives it mostly she is paranoid all the time of it dying on her. I have taken it to my work which is about 100kms to work and have even drove it the full way with the alternator light on and when I got home checked the voltage I get the same results as shown above. Shut it off after the drive and turn it back on and battery shows absolutely no sign of not being charged???? So with this happening I am really not too big on changing the alternator out for the sake of "just to be safe" when we have experienced absolutely no signs of the alternator not charging.

Does anyone know if its the alternator voltage monitoring or the current output that turns the dashlight on when low? If its the voltage at what voltage point does it illuminate it and where is that point where it is being pulled from (front off of the alternator or back at battery)? Im wondering if there is corrosion at this point and is providing a false reading to the dashboard causing the light to go on....? Am I on the right path or just bite the bullet and change out the alternator?

Any help would be appreciated.

thanks in advance

__________________
Cheers!
Bill

2002 X5 4.6is
Estoril Blue, born 11/01
~226,000km's
rebuilt tranny (11/12)
New paint (8/12)
Chain rails inspected and are good (01/13)