ac delco 12si terminal wiring?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

mumphra

mumphra

10 Year
Joined
Feb 7, 2011
Threads
19
Messages
250
Location
haverhill ma
I have been looking online now for a couple hours and I can't really find a definitive answer on a specific question about an ac delco 12si alternator.

#1 as I understand if the terminals are on the top and in a - - configuration if it internally regulated right?

#2 I know the battery terminal gets jumped to one of the terminals (or what ever configuration you want further from the battery) but the other terminal is the one in question. I dont have a indicator light... so can I just run the acc. power to it? does it need to see the resistance of a light? do I need a diode?

I wired this rig from scratch (fj40 with 350) so the simplest answer would be great so I can just run the wire and be done with it.
 
eh still not really the answers im looking for anyone else help me out. And yes I looked at google extensivly and found hundreds of answers
 
still not the simple bread down I would like.
 
Look at the picture in the link, it tells you everything you need to know.

Part number for a diode to get from radio scrap.

:meh:
 
I guess this is informative but my question is then why would I take the battery terminal not to the battery? That's the only constant I have seen in all posts.
 
In factory applications the 'batt' terminal wiring effectively fed the fuse block and charged the battery via a connection at the solenoid.



I am really failing to see what you are having an issue with.


The picture in the link provided details exactly how to wire up a 10/12si GM alternator using a diode.

:meh:
 
I know this isn't much help, but you could always return yours in for a one-wire (self-exciting) alternator... then it's a lead to the battery... done!
 
just the bat terminal confused me. I'm all set now I appreciate it thanks.
 
isnt a 12si internally regulated
 
I just noticed also that the picture that poser sent doesn't use the voltage sensing circuit... with the 12si i assume my voltage sensor/regulator is still working.
 
so I guess my question is it correct?
 
Alright 1 more thought I have a volt gauge which i assume is my "voltage sensor" so if I wire like the pic says in post 2 will this work?
 
Alright 1 more thought I have a volt gauge which i assume is my "voltage sensor" so if I wire like the pic says in post 2 will this work?
Click to expand...

No. In the pic it refers to an "ammeter" Your "volt gauge" senses voltage but it has nothing to do with the alternator sensing wire. The sensing wire in the pic of post #2 is jumpered over to the large battery terminal on the alternator which will work fine. On a one wire alternator the sensing wire is jumpered internally. The reason for the external sensing wire is so it can be wired to a location farther away where a voltage drop may occur because of a large draw such as big lighting or a fridge in the rear or a big stereo amp or AC fans. Your volt meter can be wired to any hot wire in the system but usually right to the ignition "on" switch.
 
alright so that is how it is wired right now. I have a constant 12 feed on terminal 1 and a direct line from my fuse panel load side of ignition on number 2. the problem is my voltage this way goes way up and down with rpm's So i assume I need a resister I guess to simulate the warning light? I am getting very frustrated with this and about to just use random electrical components and switch on and off untill I can afford a new 1 wire alternator and hope the 3 wire lasts until then.
 
mumphra said:
alright so that is how it is wired right now. I have a constant 12 feed on terminal 1 and a direct line from my fuse panel load side of ignition on number 2. the problem is my voltage this way goes way up and down with rpm's So i assume I need a resister I guess to simulate the warning light? I am getting very frustrated with this and about to just use random electrical components and switch on and off untill I can afford a new 1 wire alternator and hope the 3 wire lasts until then.
Click to expand...




Slow down.


Please look at the picture again.


You do not want a resistor in the signal circuit.




.
 
The issue is though I dont have a resister is it and this is what is happening I wired it exactaly like the pic said using a diode and noting regulates at all. rpm's = voltage. I think I might need a resistor to simulate the light? or is my regulator gone?
 
in it not is it
 
You must log in or register to reply here.

Share this page

Back
Top Bottom