I had to run the wire after installing the 02 PCM, as I was getting a slow blinking battery light. The addition of the wire and alternator cured that issue. Creederado and 99Silver5.3 had to do the same thing at the time also. I think that the tuners (Nelson, Wheatley, BlackBear) figured out a way around that eventually. Are you running a 99 PCM?

*EDIT* Now it's all coming back to me...been a while lol

 

I am running a 2002 PCM with a 2002 operating system. I swapped to a 145amp alternator out of an 05 silverado. The only thing I had to do was get a longer belt.

EDIT-I do however have EFI Live and I can't remember if I deleted any codes or not. The may have been it.

 

That may have been the case...IIRC, I swapped the pcm first and got the light. Then I ran the wire to my 105amp alt but the light stayed on, finally I swapped in the 145amp alt and the light went away. Creederado was the first one to figure this all out I think, but I think that he did the wire and alternator at the same time. I know for sure that guys have figured out ways around having to use the alternator and wire since I originally did mine. It's been working for me for about 4 or 5 years now so I just left it that way.

 

Well got it on and hooked up just have a "service break booster" on the DIC. So anyone know how many volts that other wire should have going to it? And also the plug is only 2 prong on the new one.

 

I'll bet that it's a battery voltage signal to the ABS system (just a guess)...I was just looking at the schematics, and realized that you have the 04 that utilizes that wire. Do you have that wire somehow hooked in to the new alternator? You could try installing the old alternator and monitoring that wire with a voltmeter to see what kind of voltage is there and possibly tap that wire into one of the other wires off the the alt (if it's deleted from the new plug)

 

Ya I was going to see if someone with the three wire one could check for me and let me know what kinda output it has on it