Alternator idiot light?

64FJ40 · Aug 23, 2010

So today I finally got around to finishing up the wiring for my alternator upgrade. It should have been pretty straight-forward since I was essentially starting from scratch.

Delco CS130 set up with an idiot light. When I turn the key on, the light comes on like it's supposed to. When I start the motor, the light goes out like it's supposed to. The problem is that it's not charging. 12.3 volts regardless of whether the motor is running or not.

All the wires are new. All the connections are solid and everything checks out ok. The only thing I can think of is that the alternator was bad out of the box. I'll pull it and get it tested tomorrow, but shouldn't the idiot light stay on then? I don't know what the light actually indicates I guess.

Thoughts?

nowires · Aug 23, 2010

Did you jump the exciter

64FJ40 · Aug 23, 2010

nowires said:
Did you jump the exciter

Edit: I read that wrong the first time. The exciter circuit is what the idiot light runs through, right?

12V+ from the iginition switch with a light bulb (and a resistor) in-line to the "L" post on the regulator. When stopped, undercharging, or if there is a fault, the regulator grounds the "L" terminal, illuminating the lamp. I didn't check the overall resistance of the circuit, but I will do that when I get home.

CrustyJeep · Aug 23, 2010

64FJ40 said:
Thoughts?

Yes, use an idiot light for oil pressure. Use a volt gauge for charging.

That's what you wanted to hear, right? :flipoff:

64FJ40 · Aug 23, 2010

CrustyJeep said:
Yes, use an idiot light for oil pressure. Use a volt gauge for charging.

That's what you wanted to hear, right? :flipoff:

I have a volt gauge, too. It says the alternator isn't charging. :flipoff:

nowires · Aug 23, 2010

http://www.youtube.com/watch?v=ODYcBkmHtoE

Hope this helps
I also started a search and was coming up with all sorts of stuff

64FJ40 · Aug 23, 2010

nowires said:
http://www.youtube.com/watch?v=ODYcBkmHtoE

Hope this helps
I also started a search and was coming up with all sorts of stuff

That's a 10si (or maybe a 12si). They're a bit different in terms of wiring.

PUO-BANNED · Aug 23, 2010

This might help

http://www.alternatorparts.com/cs130_sbpage4.htm

oops. http://www.alternatorparts.com/cs130_sbpage3.htm

64FJ40 · Aug 24, 2010

PUO said:
This might help

http://www.alternatorparts.com/cs130_sbpage4.htm

oops. http://www.alternatorparts.com/cs130_sbpage3.htm

Thanks. I even had that one bookmarked but forgot there was a troubleshooting section.

I'm not sure if I should be relieved it's wired right, or bummed because the brand new alternator that I ordered like a year ago was bad the whole time.

64FJ40 · Aug 24, 2010

PUO said:
This might help

http://www.alternatorparts.com/cs130_sbpage4.htm

oops. http://www.alternatorparts.com/cs130_sbpage3.htm

Update for those that are following along (or are stupid enough to click on my thread looking for information:haha

Alternator tested good.

All of my connections test good.

Then I checked the idiot light circuit. 1250 ohms. According to http://www.alternatorparts.com/cs130_sbpage6.htm it's supposed to be between 35 and 500. When I remove the resistor and run just the lamp, it's only 11 ohms and still doesn't work right. So I'm off to dig through parts bins to find a resistor that will work.

It's a learning experience...

PUO-BANNED · Aug 24, 2010

glad I could help a little. is this on a toy engine or a chev?

an alternator off a mid 90s' buick 3.8 has the right clocking for a stock chev V8 pass side mount and will bolt right in. My dad has one on his 47 but has a harness to make it a 1 wire I was over there tonight but neglected to look at the wiring setup.

64FJ40 · Aug 25, 2010

PUO said:
glad I could help a little. is this on a toy engine or a chev?

an alternator off a mid 90s' buick 3.8 has the right clocking for a stock chev V8 pass side mount and will bolt right in. My dad has one on his 47 but has a harness to make it a 1 wire I was over there tonight but neglected to look at the wiring setup.

Stock 1964 F motor in this one. No such thing as a bolt-in anything :booo:.

I apparently don't own a single resistor that will get me in the right range. :looser: Instead of screwing around with it I'll just get the right one tomorrow and hopefully be done with this.

64FJ40 · Aug 25, 2010

Apparently this owns me. :booo:

Several iterations of wiring configurations that are supposed to be correct yield no results. When I plug it in, there is definitely a load on the drive belt once the field is energized. If I screw around with different resistors in the exciter circuit, I can make it put out anywhere from 11.96 to 12.36 volts.

I'm taking it to an alternator shop to get it tested. The fact that the O'Reilly parts kid needed a part number in order to hook it up to his machine didn't inspire a ton of confidence even though the machine said it "passed".

PUO-BANNED · Aug 26, 2010

I can go look at my dads rig tomorrow if you want the one wire setup. his uses a volt guage and no dummy light, in fact I don't think it has a resistor unless its part of the harness he has on the back of the alt.

It's like that backwoods goop ****, sometimes you have to throw the service manual away and just wing it. :haha:

Binder · Aug 26, 2010

If you put it together initially with not enough resistance it likely toasted the alt.

t1h5ta3 · Aug 26, 2010

have you tryed conecting the " s" terminal? i know it suposedly doesnt have to be connected, but it cant hurt..

64FJ40 · Aug 26, 2010

PUO said:
I can go look at my dads rig tomorrow if you want the one wire setup. his uses a volt guage and no dummy light, in fact I don't think it has a resistor unless its part of the harness he has on the back of the alt.

It's like that backwoods goop ****, sometimes you have to throw the service manual away and just wing it. :haha:

If it's easy, then I'd be interested in how a standalone harness would be set up.

Binder said:
If you put it together initially with not enough resistance it likely toasted the alt.

Possible, which is why I want to get it tested by someone more knowledgable than the kid at O'Reilly's to see if I fried the regulator. Initially it had too much resistance, and I've tried multiple configurations between 11ohms 1watt, 100ohms 1/2watt, 100ohms 10watt, and various combinations.