oange ss

iTrader: (50)

Having charging issues with my swap, can anyone tell me what the generator turn on signal is suppose to be for a 2001 f-body pcm, currently have 10 volts, thank you

crainholio

iTrader: (2)

How do you have the pin wired, to the PCM or somewhere else?

oange ss

iTrader: (50)

PCM, C15 pin

Pocket

iTrader: (22)

10v means you're on battery power. Have the alt tested and make sure the wire on the backside isnt broken

oange ss

iTrader: (50)

Voltage gauge shows 12.5 volts, voltage on alternator exciter wire shows ~ 10 volts. I thought I read somewhere exciter wire is suppose to be 5 volt signal.....thanx for all the replies

Pocket

iTrader: (22)

Its approx 9v

Gauge should read 14.4v for a fully charging alt during run

oange ss

iTrader: (50)

Thanx, i'll double check exciter wire for integrity..voltage gauge was swinging last time i had it out between 12 and 14 volts

oange ss

iTrader: (50)

On a side note, the harness was a 98 f-body i converted to 99+ specs with a 99+ pcm however the alternator is still 98... would the alternator being a 98 make any difference ?

crainholio

iTrader: (2)

I just jumped on NAPAonline and checked part numbers, '98 is a different part# than '01...so they may not be compatible.

oange ss

iTrader: (50)

Cool, that may be the problem. I assumed the alt were the same but just different control systems. I'll track down a newer alt and try that.

Pocket

iTrader: (22)

As long as you moved the alt exciter wire to the PCM, it will work fine

Tongboy

I was just fighting a dead alternator - exciter wire was ~1 volt less than battery voltage.

You can test the alternator by hard wiring the exciter wire to 12volt - you aren't going to hurt anything running it for a few minutes that way. You can also wire it to a battery light in the car if you wanted to do it that way.

oange ss

iTrader: (50)

good info thanx, hopefully can make it out to the garage tonight and get it figured out....thanx for all the replies

LS1MCSS

iTrader: (18)

I have tested two f-body setups and approx 10 volts is what the generator turn on wire is supposed to put out. Sounds like you're getting the right signal to the alternator.

oange ss

iTrader: (50)

sweet ! thanx for the info....After further evaluation, it seems I have everything wired correctly and all the wiring is good. I wired up an idiot light under the hood to simulate a dash light and the alternator wont charge that way either. I have a good alternator coming from a fellow Tech member, hopefully my troubles will be over soon. Thanx everybody

BlakeLan2010

I'd like to hear if the new alt solves your problems

oange ss

iTrader: (50)

It would have, kinda. I was removing the alternator in preparation for the new one when it got here and noticed there was no nut on the battery charging wire stud. Apparently some dumbass had forgotten to put it on and the wire was just bouncing around on the stud causing my issues. So there you go, no matter how good you remember installing parts always double check everything when troubleshooting a problem. I knew that but thought I had everyhting covered. Thanx to everyone who helped me out.