Alternator won't charge

v6camaro4life · 06-03-2023, 08:21 PM

So my alternator was going bad, I got a new one pulled the old one and i broke the pigtail connecter and fixed it put the new alternator in and put everything together and boom alternator not charging. Battery light comes on and service battery charging system. well i pulled the alternator again and got it tested, it was bad, so I exchanged for another one got this tested twice before getting put on, and it works perfectly fine. Put it on and get everything hooked up started the car and car is still not charging.

Things I have done to find the issue. I have a test light and put it on all terminals with hot and they are all getting power, alternator is getting power on main line. the 350amp fuse in the trunk is fine, and the 200 amp fuse under the hood is fine. if battery is charged car runs and drives perfectly fine everything works like suppose to but alternator is still not charging.

I've talked to some people and they believe my ECU could have gone bad or shorted out specifically the charging system in the ECU to turn it off or on. idk how true that is but someone please help me. I have been without my car for a week.

It is a 2016 2SS Camaro everything is stock.

LT1Vert50th · 06-24-2023, 06:53 PM

Quote:

Originally Posted by v6camaro4life

So my alternator was going bad, I got a new one pulled the old one and i broke the pigtail connecter and fixed it put the new alternator in and put everything together and boom alternator not charging. Battery light comes on and service battery charging system. well i pulled the alternator again and got it tested, it was bad, so I exchanged for another one got this tested twice before getting put on, and it works perfectly fine. Put it on and get everything hooked up started the car and car is still not charging.

Things I have done to find the issue. I have a test light and put it on all terminals with hot and they are all getting power, alternator is getting power on main line. the 350amp fuse in the trunk is fine, and the 200 amp fuse under the hood is fine. if battery is charged car runs and drives perfectly fine everything works like suppose to but alternator is still not charging.

I've talked to some people and they believe my ECU could have gone bad or shorted out specifically the charging system in the ECU to turn it off or on. idk how true that is but someone please help me. I have been without my car for a week.

It is a 2016 2SS Camaro everything is stock.

Have you try changing or adding a negative cable. I heard something about Gen 6 Camaro Negative cable issues...

SSDan · 06-24-2023, 07:45 PM

Adding an extra ground cable is helpful on 2016 V8 models that experience a slow crank on a hot engine (heat soak issues). For your problem I have nothing to add beyond what you have tried except maybe to make sure you have a good battery (get it load tested). I hope it’s not your ECU/BCM. That sounds complicated and expensive. Good luck.

ctrlz · 06-25-2023, 06:48 AM

Some pictures of that pigtail might help.
I would make some jumpers so you can test the alternator on the car. You need to energize the field windings and see if you can measure that the alternator has an output. There are probably only a few connections on the pigtail.
I think either your alternator windings are not getting power or your output wire is open. If you have a spare battery or 12V power supply you could energize the windings without the car battery and see if you get output. Also, it would have been nice to check the most recent failed alternator. If you wired the something backwards you may have blown a diode.

I checked the diagram in the repair manual. Your pigtail should have three wires.
red/yellow - output
gray - Field duty cycle signal
brown - Charge ind ctrl

The other connection is the ground (bolted to engine).

EDIT:
I have done some searching to try to figure out exactly how this system works, and the link below is the best I have come up with.
The two main modules involved are the BCM and the ECM. The voltage regulator within the alternator also acts as a mini-module.
The feedback sequence seems to be gray wire reports alternator duty cycle to BCM. BCM reports to ECM. ECM controls the alternator via brown wire ("turn on signal").
https://ricksfreeautorepairadvice.co...er-management/

06-03-2023, 08:21 PM	#1
v6camaro4life Drives: 2014 LT 3.6l camaro Join Date: May 2020 Location: 37381 Posts: 3	Alternator won't charge So my alternator was going bad, I got a new one pulled the old one and i broke the pigtail connecter and fixed it put the new alternator in and put everything together and boom alternator not charging. Battery light comes on and service battery charging system. well i pulled the alternator again and got it tested, it was bad, so I exchanged for another one got this tested twice before getting put on, and it works perfectly fine. Put it on and get everything hooked up started the car and car is still not charging. Things I have done to find the issue. I have a test light and put it on all terminals with hot and they are all getting power, alternator is getting power on main line. the 350amp fuse in the trunk is fine, and the 200 amp fuse under the hood is fine. if battery is charged car runs and drives perfectly fine everything works like suppose to but alternator is still not charging. I've talked to some people and they believe my ECU could have gone bad or shorted out specifically the charging system in the ECU to turn it off or on. idk how true that is but someone please help me. I have been without my car for a week. It is a 2016 2SS Camaro everything is stock.

06-24-2023, 07:45 PM	#3
SSDan Drives: 2016 1SS 6MT NPP Join Date: Feb 2010 Location: Lake Murray, SC Posts: 2,243 View My Garage	Adding an extra ground cable is helpful on 2016 V8 models that experience a slow crank on a hot engine (heat soak issues). For your problem I have nothing to add beyond what you have tried except maybe to make sure you have a good battery (get it load tested). I hope it’s not your ECU/BCM. That sounds complicated and expensive. Good luck. __________________ 2016 Camaro 1SS Hyper Blue 6MT NPP 2010 Camaro 2SS Cam/Headers/CAI/3.91 gears 476 rwhp/440 rwtq (sold)

06-25-2023, 06:48 AM	#4
ctrlz Drives: 2017 2SS, 50th pkg, M6, MRC, NPP Join Date: Jan 2016 Location: Ocean City, NJ Posts: 3,175	Some pictures of that pigtail might help. I would make some jumpers so you can test the alternator on the car. You need to energize the field windings and see if you can measure that the alternator has an output. There are probably only a few connections on the pigtail. I think either your alternator windings are not getting power or your output wire is open. If you have a spare battery or 12V power supply you could energize the windings without the car battery and see if you get output. Also, it would have been nice to check the most recent failed alternator. If you wired the something backwards you may have blown a diode. I checked the diagram in the repair manual. Your pigtail should have three wires. red/yellow - output gray - Field duty cycle signal brown - Charge ind ctrl The other connection is the ground (bolted to engine). EDIT: I have done some searching to try to figure out exactly how this system works, and the link below is the best I have come up with. The two main modules involved are the BCM and the ECM. The voltage regulator within the alternator also acts as a mini-module. The feedback sequence seems to be gray wire reports alternator duty cycle to BCM. BCM reports to ECM. ECM controls the alternator via brown wire ("turn on signal"). https://ricksfreeautorepairadvice.co...er-management/ Last edited by ctrlz; 06-28-2023 at 09:57 AM.

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