So is W/L the Vref for the alternator? I just re-opened the wiring diagram, and even though I reminded myself 50 times while sitting there staring at it... for some reason, I mixed up W/B as being White/Blue....

Anyway... since that wire is cut, I guess the alternator doesnt know that its putting out too much?

 

I posted a diagram of the S5 alternator. It shows that the terminal which is closest to the B+ terminal is the terminal that is to receive constant voltage. Seeing this would make it easy to figure out whether or not you had the wires accidentally switched or not. One quick glance will tell you such.

 

is the JSpec harness any different? I could swear that one of the wires coming off of the alternator was Yellow/Blue... it wasnt with the best flashlight, and it was a little dirty... but I'm pretty sure. Tomorrow is another day...

 

ok, so voltage at the battery while the car is running remains ~15.5V, I hooked the W/L wire back up and there was no change in voltage.... back to square one...

On another note, the harness must be for an S5... as the alternator wasn't just rigged up, it was using a factory harness for as far as I could follow it.

 

Takes but a minute to test the output of the alternator.

 

the alternator has a Built in regulator..It is not Governed by anything else on the car.
If the regulator is bad,or going bad,it will Screw with the Output of the alternator and either put out Low,fluctuating voltage,.Or HIGH excessive voltage.
You shouldn't have any more than 14.4...after that you are asking for something to Fry.
..question:..What Engine harness do you have on the car,hooked up to the engine?
you never really stated that.