01WS6/tamu

iTrader: (37)

Ok I left the diagrams at the shop. The vette and the f-body alternator both use a single red wire running to the pcm that goes in the same pin location for either a vette or f-body. However, the vette alternator uses an additional gray wire that is called the field duty cycle and runs from the pcm to the alternator. Do I just need to add this wire into the harness and pin it in at the pcm, and alternator in the same location that it is on a vette or do I need to do something different. Anyhow if someone has a few minutes and has done it in this application I'd appreciate it. thanks

G-Body

iTrader: (4)

I have never done it, but you can make it work. I don`t know if you can do it using the PCM, but if you hook the second wire to a +12V ignition source it will work. I attached the diagrams (I didn`t have diagrams for a vette so I attached one for a truck as they both use the same style alternator regulator)

01WS6/tamu

iTrader: (37)

Since the red wire is essentially correct. Is it correct to assume that I need a non resistored 12v in crank and run on the gray to make it charge then?

G-Body

iTrader: (4)

Yep, you have that correct.

*You may be able to hook the grey wire to pin 52 on C2 and use that, but I`m not positive on that, I don`t know if all the 99-02 PCM`s use the same internal circuitry*

LS1GMCTruck

iTrader: (2)

What if you don't have the field duty cycle gray wire in use on your Vette alternator? What is its function? Way back when, when I had Jesse Bubb modify my F-body harness & told him I was using the Vette alternator, it simply came with the single red wire on the aternator plug(?). Thanks

andrew69_04

iTrader: (148)

I didnt ever think about that, but im running a F-body harness in my S10 with the vette alternator. Only using the original single red wire from the alternator and it works great. have almost a 1000 miles on it and absolutely no charging/starting/dead battery problems yet. i would say forget the gray wire.

LS1GMCTruck

iTrader: (2)

Thats how I've been running mine as well, knock on wood, no problems, thats why I ask about the gray wire.

01WS6/tamu

iTrader: (37)

Got the truck running last night, early this morning woohoo. However the alternator charges like a house on fire and after the engine runs about 20 seconds the damm charge light comes on but the damm thing stays charging. I ran both the red and gray back to the pcm from the alternator. However I went back to the shop at midnight and grabbed a 02 vette diagram. They show a third wire on pin D that goes to 12Vconstant. Could this be the problem. The other thing that has me stumped is that on the back of my regulator where the plug goes in it is marked S F L like the v6's and fbodies use. However on the all data diagram they are marked DCB C gray wire B is the red wire. Anyhow anyone know WTF I can do to get this bitch working right. I am all ready pissed the fresh trans has all forward gears and no reverse. It is the high output valeo alternator if it makes a difference. The code it is setting is a p1637 but I just pulled a diag chart at work now. It does not seem very long to work through.thanks guys

01WS6/tamu

iTrader: (37)

For 98-03 s10 guys I found out a little something tonight. It will charge perfectly with only the red wire hooked up going to the pcm. However, the charge lamp on mine stayed on. I added the third pin into the plug and hooked up all three wires. red and gray go to the pcm. The third I jumped over to the bat + post just like it showed on my alldata, the lamp went out and the pcm began regulating as necessary. According to all data without this wire it will charge at a fixed rate of about 65-70 percent output. With the third BAT wire hooked up the pcm has full control of the alternator. Hope this helps someone else out who fires their pride and joy off at 3 in the morning only to be met with troubles. If you purchased a harness from CPF speartech etc then you will not have to do this. This is for those that built their own harness' at home.

Jaysz28

iTrader: (19)

good info.... I hope to do a swap like this in my '02 Sonoma......

Gotta finish up the ls1/t56 swap in my firebird first.... one project at a time!

-jason

Scoggin Dickey

iTrader: (34)

This thread is full of truth. You need either one wire or all three in most cases using the Vette alternator. All three is the better setup.