pcmhacking.net

hey people. my build has a pcm regulated altinator (05 vz holden ls1) im changing the os to suit 3bar dbc and SD and before i get to it wanted to check the outputs will still work. its pin 15 and 52 on my pcm but the standalone harness i have does not have 52 wired. if i run the wire will it still work?

normal pinout as per loom

original wiring

i think i may have found it. can anyone confirm. i move pin 52 to pin 75. so pins 15 and pin 75 on first picture

The Generator Field Duty Cycle signal is technically not needed. It's just a check the PCM can do on the alt. All you need is to have the single wire "turn on/off" signal. I assume this is the same for your setup. I have used both in the past and also just the single wire. Works either way. PCM checks system voltage and kicks on the alternator with one wire (in your case pin 15). Totally up to you if you want. I am not sure what the benefit is exactly other than maybe the PCM letting you know the alternator is going bad or is bad.

i guess the question is what logic is behind the activating of that wire, does it allow it to charge the battery more smartly or does it just have on when engine is running or not ?

codemanrose wrote:The Generator Field Duty Cycle signal is technically not needed. It's just a check the PCM can do on the alt. All you need is to have the single wire "turn on/off" signal. I assume this is the same for your setup. I have used both in the past and also just the single wire. Works either way. PCM checks system voltage and kicks on the alternator with one wire (in your case pin 15). Totally up to you if you want. I am not sure what the benefit is exactly other than maybe the PCM letting you know the alternator is going bad or is bad.

cheers mate. i am building the loom and don't want to be trying to add shit later on. so will run it in and if it works it works. thanks for the answer.