I swapped a 2000 ls1 from a camaro and cant get the alternator to charge I had it checked 3 times at autozone and it passed the tests Currently I have r15 to pin b on the back of the alternator and the wire is putting out 9.53 volts and I have the +Post wire to the starter however no charge at all.

 

I looked at my alternator connector and didn't see pin letters (maybe it's under the rear cover). The wire went to 2nd from the right as viewing the back of the connector with clip on top.

 

Thats what I have. Second pin from the right if your in the drivers seat

 

How are your grounds ?
What condition Is that tiny wire going to the pigtail in ?

 

do you only have 2 wires connected to the alternator? the camaro alternator is a bit more picky on how its wired compared to the truck version. there's a pretty big thread on 'tech regarding the differences in the conversion section, but i don't think we can direct link to another forum...

 

What wire is putting out 9.53volts? What are you talking about here? The wire going from the ALT to the battery? Or the exciter wire coming from the PCM?

Where did you measure this 9.53 volts from?

That little wire I THOUGHT was only carrying 5 volts from the PCM. Did you mess with the pins in the PCM connectors by chance?

The best way to test that wire is to do a continuity test between the PCM connector and the plug for the ALT. It took me a lot of trouble shooting to finally realize that that little wire was burnt inside of the plug.

The best fix for this is a GM replacement pigtail. It will come with 5 wires already pinned, and they are heavier gauge than original. So you make the splice about a foot away from the alt. Helps with heat/vibes, which is what kills that wire in the first place I think. And, you have 4 spares if you de-pin it and save them.

Its a pretty simple set up from there. PCM sends a signal to the alt...alt charges. Check your grounds like others mentioned. Double check your big 3 wires and battery connections. I think you can also give voltage to the alt manually to rule out a problem with the PCM's signal.

J.

 

the issue that pops up on the fbody alternators from time to time is that there was a light in the 4th gens inline with one of the wires that drops the voltage (i *think* to pin B); without the light (or a resistor) in line, the alt gets a bad reading and doesn't charge properly. the truck alternators don't have this wire, so its not an issue for everyone

 

Ive read that before.

Weird...as my 99 harness didnt have anything interrupting the wire from the alt to the PCM. At least not that I saw. I have no alt light or anything wired up. Kinda weird how thats a random problem for people.

J.

 

thats only the 98 that used the bulb as a resistor. the 99-02 use the pcm to provide the voltage to it.

 

Ok well today was an unproductive day I checked my grounds... checked the rev to 3k and also checked the little plug... and still no charge.

 

your wire should be at cavity B on the connector (make sure the pin is fully seated I have seen these pushed back before)

if this is the case and still does not work you can run a 470 ohm 1/2 watt resistor in line from the connector to switched in run positive 12v or for testing just to the battery positive

 

Yea I might try that tomorrow and see if that doesnt work im going to buy a truck alt and see if that works

 

ok well I tried the 470ohm resister and it doesnt change the voltage it stays at 12v which is what my battery is at

 

Did you just put the resistor in your current line... Or did you run it wiht a separate switched 12v source like 88 was suggesting?

If you run the 12v source, with the resistor to that alt, and its still not working, then you either have bad cables, or the alt is junk. Regardless of what the "duratester" says.

Also did you do a continuity check from the plug end out to the PCM connector? Not the back side of the plug, but the actual inner pin...like the alternator's connections would see. Mine gave two different results because the connector pin was broken way inside the plug.

J.

 

I connected a wire straight from the battery and to the resistor 470 ohms and used a volt meter to test the voltage on the wire with or with out the resister it stayed at 12v so i didnt go any farther.

 

I also tested the plug every direction possible

 

Huh...Where are you located? Im pretty sure I have a good spare alt you could test. I know you tested it at the zone...but Ive used that machine 1000s of times...and I have seen it give out a false PASS here and there.

If your wiring all checks out, and you've hot wired the alt with zero response...then I think the answer is looking pretty clear. Get ahold of a known good one, or buy a reman and test it out that way.

J.

 

Hey ghetto... I think I found my problem the dumbass company sent me the right alternator with the wrong regulator... If I give 12v on pin c for 2 secs its kicks right up and works perfect... So im going to run pin c to 12v and call it a day.

 

are you giving it pure 12v? you dont want to burn out the regulator

 

Im using pin b gets 10v and pin c gets 12v

 

anybody see a problem with that?