 ALT light troubleshooting. FIXED, Specifically, what makes it come on? |
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| malcolm2 |
 Jul 31 2016, 06:03 AM
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#1
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Advanced Member  Group: Members Posts: 2,747 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States 
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I noticed the last time i parked that the red "G" light had come on slightly. Got in yesterday and it was on bright and the volt meter was at 10.5. Revving the engine did not help either.
I checked the belt tension and decided to tighten it. Took a 20 minute drive to Nashville and all was well. At the last stop i saw the dim G light again. Then bright for a while. Then out. What is the prognosis? I have about 20k miles on the alt wire harness and gel battery. Maybe 10k on the rebuilt alt. |
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| Spoke |
Aug 3 2016, 04:45 PM
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#2
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Jerry Group: Members Posts: 7,169 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None
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Definitely a good sign. It shows the alternator can charge the battery. Gotta make sure the diodes in the VR circuit are ok.
Did the GEN light go off? |
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| malcolm2 |
Aug 3 2016, 04:58 PM
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#3
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Advanced Member Group: Members Posts: 2,747 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States
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QUOTE(Spoke @ Aug 3 2016, 05:45 PM)  Definitely a good sign. It shows the alternator can charge the battery. Gotta make sure the diodes in the VR circuit are ok. Did the GEN light go off? with the jumper attached, I start the engine. It idles at 800 rpm, VOM is reading 12.5 and the light is on. Rev the engine to 2500, VOM raises to 12.8 the light dims, Rev to 3000 vom raises to 17 and the light goes out Return to 800 and the light stays out. In the past, once I started the car the G light went out and stayed out. |
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Posts in this topic
malcolm2 ALT light troubleshooting. FIXED Jul 31 2016, 06:03 AM
Rand If you're lucky, it's just dirty contacts ... Jul 31 2016, 10:51 AM jim_hoyland This write covers your question and a lot more:
h... Jul 31 2016, 05:32 PM jim_hoyland Another good source is Ratwell's:
http://www.... Jul 31 2016, 06:06 PM
malcolm2
Another good source is Ratwell's:
http://www... Aug 1 2016, 08:16 AM malcolm2
[quote name='jim_hoyland' post='2378911' date='Ju... Aug 2 2016, 07:41 PM Spoke
I took the plastic cover off of the board behind ... Aug 3 2016, 06:38 AM malcolm2
You can test the alternator by removing the VR a... Aug 3 2016, 07:01 AM malcolm2 I also checked the Ohms on the VR per the Ratwell ... Aug 3 2016, 07:04 AM Spoke
site says: I GOT:
•D+ and DF - 0.3 o... Aug 3 2016, 10:59 AM malcolm2
[quote name='malcolm2' post='2379860' date='Aug 3... Aug 3 2016, 01:53 PM Spoke
You can test the alternator by removing the VR ... Aug 3 2016, 10:54 AM malcolm2
You can test the alternator by removing the VR... Aug 3 2016, 03:10 PM malcolm2 I did "search" but rarely found a fix. ... Jul 31 2016, 07:35 PM Rand ..... Aug 2 2016, 09:18 PM malcolm2
I started her today and after a 10 minute warm u... Aug 2 2016, 09:22 PM jim_hoyland This type of problem has always baffled me too; :... Jul 31 2016, 08:01 PM bretth I haven't had the opportunity to dive into my ... Jul 31 2016, 10:30 PM catsltd Mine did the same as your car.Even the 10.5 volt t... Aug 1 2016, 08:24 AM Rand [edited] I saw that too late. :D You're on it. Aug 2 2016, 09:28 PM malcolm2 just checking around to purchase a VR, if needed.
... Aug 3 2016, 11:14 AM Spoke The alternator seems to be at least providing volt... Aug 4 2016, 09:36 AM malcolm2
The alternator seems to be at least providing vol... Aug 4 2016, 09:57 AM Spoke
The alternator seems to be at least providing vo... Aug 5 2016, 10:09 AM worn
I noticed the last time i parked that the red ... Aug 4 2016, 01:20 PM malcolm2
Try:
[url=http://www.pelicanparts.com/techarticl... Aug 4 2016, 01:55 PM worn
Try:
[url=http://www.pelicanparts.com/techartic... Aug 4 2016, 05:35 PM Spoke
Paragraph 2 is what SPOKE suggested and it gave m... Aug 5 2016, 10:23 AM malcolm2
How many times have you repeated the DF/D+ short... Aug 5 2016, 11:42 AM Spoke
[quote name='Spoke' post='2380889' date='Aug 5 20... Aug 5 2016, 02:14 PM malcolm2 Heading home now. FedEx said they are should be th... Aug 5 2016, 02:56 PM malcolm2 well damn, I did the D+/DF short test once more an... Aug 5 2016, 03:36 PM malcolm2 Cancel that post.... 4th time I got the light to ... Aug 5 2016, 03:49 PM ClayPerrine Sounds like something in the alternator wiring. I ... Aug 6 2016, 06:50 AM Spoke
Sounds like something in the alternator wiring. I... Aug 6 2016, 09:18 AM malcolm2
Sounds like something in the alternator wiring. I... Aug 6 2016, 11:27 AM malcolm2 The bitch is out. I rang out all 4 wires and they ... Aug 8 2016, 07:49 PM Spoke I have tested diodes on an alternator but you have... Aug 9 2016, 12:19 PM malcolm2 I took mine and 1 other unknown spare for testing ... Aug 9 2016, 02:25 PM malcolm2 Rebuilder said the brushes were worn down enough t... Aug 10 2016, 12:57 PM malcolm2 3.5 hours and the rebuilt alt is in. No heat excha... Aug 11 2016, 07:33 PM Spoke Nice!
:beer2: Aug 12 2016, 07:15 PM |
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