Alternator ID Question
 

After many hours of testing, contact cleaning, I've come to the conclusion my alternator is bad. 12.59V at battery when off, drops to 12.2 Volts when running.

I've decided to replace rather than rebuild.

How do I know if I have an internal or external voltage regulator?

Identifying Alternator Type......
 

Dave,

A quick look into your engine compartment (left inside) will show if the car is using an external voltage regulator or not. The absence of a VR is a sure indication that your alternator has been upgraded or changed to an alternator with intrgrated VR.

Another check is to look at the alternator wiring. The new alternator with ingrated VR does not use the DF terminal. The red wire goes to B+, 2 brown wires go to D-, and blue wire goes to 61. And finally, look at the back side of your alternator and inspect for the integrated voltage regulator.

Tony

as said above just look at the back of the alternator for the integrated VR.

Thanks folks, it does appear that the VR is integrated. I read the tech bulletin and from the pictures it appears the alternator cover has been upgraded for the internal VR, with a "cutout" portion of the cover.

From the voltage readings above, does my diagnosis seem correct?

Yes, you should be seeing higher than 13.0v if the system is charging. Means the alt is bad or the VR is bad. You MIGHT try the full field test to isolate the problem to the VR, but be prepared to replace the alt.