Battery Light?
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Tuned
Joined: Mar 2014
Posts: 452
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From: Cheyenne Wy.
Battery Light?
Today on the way home from work the battery light came on for a few seconds, I happened to have the SGII on the voltage setting and it was 13.6 at idle and 13.9 when I got up to speed. The FICM voltage was at 48.5. Alternator is stock and batteries are 2yrs old. The light never came back on. Headlights and heater was on. 
Senior User
Joined: Oct 2004
Posts: 422
Likes: 0
From: N. Carolina
Mine's been flashing sporadically too ... last two days though, I noticed my battery voltage momentarily drop (I have an Edge CS) to < 12 from 13.5+ at highway speeds when the light would flicker. So ... I say its alternator time.
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Tuned
Joined: Mar 2014
Posts: 452
Likes: 2
From: Cheyenne Wy.
Thanks
Thanks for the reply's. Just an update it came on again this morning about the same parameters as last night. Just got on the off ramp coasting down from 80 mph it comes on and my volts are at 13.7 when I get to the stop sign the light goes out volts steady at 13.5 and go up to 13.9 as I accelerate away. at 80 mph the volts are 13.9 to 14.1. All this with lights and heater on. I will check grounds this weekend if I have a weekend!!
Lead Driver
Joined: Dec 2006
Posts: 6,496
Likes: 94
From: So. Jersey
Since your alternator is stock and if everything else checks out, I'd suspect one of the brushes are wore down to a point it's barely making contact. You could take it apart and check.
Here's a result from a quick search.
Here's a result from a quick search.
Hotshot
Joined: Dec 2003
Posts: 15,369
Likes: 121
From: Stuttgart, Ar
It might be happening too fast for the SGII to detect the drop. If the light is flashing it's for a reason.
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Senior User
Joined: Jul 2014
Posts: 435
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From: Bloomfield, NM
my old truck did that for about 3 months. till all of a sudden one day it came on and stayed on. lasted long enough to get to auto zone, buy and alternator, drive to my shop, and pull it in. as soon as I got in the shop, it started sputtering and then everything went quiet.
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Postmaster
Joined: Sep 2010
Posts: 3,472
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From: Southern Cal
I agree with 87crewdually. When alternators start to go bad, the worn brushes will randomly work, especially at first start when cool, and give the impression all is well. After a bit, they start to loose contact with the armature and work more and more intermittently.
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Tuned
Joined: Mar 2014
Posts: 452
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From: Cheyenne Wy.
Just one last question, I am getting an alternator after the holidays are over, the battery light sometimes will stay on for 3-4 minutes and no changer to SGII volts or FICM volts, I know the SGII seams to be working because it usually shows 11.5 volts while the glow plugs do their thing then it is back to 13.6 to 14 volts. While the light is on for 3-4 minutes the volts don't drop below 13.7 volts. and yes I will be looking for a 140 amp minimum alternator.
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