Hey guys, so the battery light on my dash is flashing when I have my accessories turned OFF. I can't seem to figure out why. My alternator and batteries are both new and it's still doing it. If I turn my headlights on, or my ac AND radio, or my KC lights, it stops flashing though. I'm stumped. Any ideas? Sometimes if I have everything off but have either my Ac or my radio (just one) on it will still flash but it's weaker and more intermittent. Then when I turn both on it stops just like it does when I turn the headligts or kc's on. If all the accessories are off it will also stop flashing when I open the door and the dome light comes on. It will also stop or weaken if I lower my power windows. It seems like it just flashes until I put a load on the system, then it realizes there's power and stops flashing. Not sure how to locate the issue. Anyone else dealt with this before?
Battery light
- Thread starter TexasJ
- Start date
lincolnlocker
Well-known member
Check all the grounds to the block and back of the heads. And retest batteries and alternator. Even if new like you said.
live life full throttle
live life full throttle
I do have to ask does anyone know the total of grounds there are to check 
. A little bit of a smartass question but knowing electical and what i know of these trucks what (in my own terms) would your main, primary, secondary and ancillary grounds be.
Sent from my SM-G930V using Tapatalk
. A little bit of a smartass question but knowing electical and what i know of these trucks what (in my own terms) would your main, primary, secondary and ancillary grounds be. Sent from my SM-G930V using Tapatalk
dmd
Member
There was some goofy thing about brake lights on some of the OBS trucks too sometimes, I remember
someone mentioned that in the past. May be something to check to verify they are
good bulbs.
someone mentioned that in the past. May be something to check to verify they are
good bulbs.
dmd
Member
Rear of the truck, or the interior light. One of those could cause some strange grounding issues on one era of truck. Going from memory of an article i read.
Just a thing to check
Just a thing to check
Bugman
Active member
Have you tested the output of the alternator at idle with everything off and then with things turned on. I'm betting that the alternator is putting out too much voltage.
I checked it at idle with everything off and it was fluctuating between 14.7 and 15. Didn't check with everything on. The battery light was flashing with the old alternator though too...
Bugman
Active member
Then I would say that there is a wiring problem between the light and the plug on the alternator or it is the alternator.
The exciter voltage for the alternator goes through that light. If you pull the battery light out the alternator will not charge the battery.
Have you don't any wiring where you might of connected something into the wire from the light for 12 volts?
The exciter voltage for the alternator goes through that light. If you pull the battery light out the alternator will not charge the battery.
Have you don't any wiring where you might of connected something into the wire from the light for 12 volts?
rusty1161
Member
Does the light also indicate voltage that is too high?
Rusty
Rusty
rusty1161
Member
psduser1
Well-known member
Bugman
Active member
I have heard of instances where it does but I haven't seen it.
Basically it gets it power through the key switch and it's ground from the alternators stator winding. Once the alternator starts charging the ground will go away and turn out the light.
Basically it gets it power through the key switch and it's ground from the alternators stator winding. Once the alternator starts charging the ground will go away and turn out the light.
lincolnlocker
Well-known member
Yep. Voltage regulator is fubar15 is too high, I'd think the regulator isn't operating properly.
live life full throttle
Are you asking if I've connected any wires to the wire that goes between the battery light and the alternator? If so, the answer is no. However, I have put in a dixie horn and 3 pairs of different kc lights, but I made a custom fuse panel for all that. It all goes to ground on it's own and the fuse panel goes directly to the battery. That said, the battery light was also flashing long before any of those accessories were added ao it's not any of that.
See that's what I thought too but that's why I replaced tje alternator the first time. This new alt isn't even 6 months old. Is there anything else it could be?
lincolnlocker
Well-known member
Nope.. they only have a signal wire that tells it to charge. And that is basically key on power so as soon as it spins its charging. But i think its supposed to be between 13.8v and 14.5v.... any more is bad.
live life full throttle
Ok, thanks. Is it possible that there is a short to ground somwhere causing the regulator to go bad? Or is that even possible? Just wondering if there's something else causing the regulator to go bad or if it's just a dud.
lincolnlocker
Well-known member
I have swapped them every year since i put one from advanced auto parts on my dually. Nothing compares to the oem one unless you spend a lot more for one.
live life full throttle
Damn...ok. The one I got was a high output alt. Like 230 amp instead of 110 or whatever the stock was. Cost me an extra 150 or 200 bucks but I figured it would last me awhile...
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