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Battery Light on... Was thinking alternator until...
...the voltage corrected today...
so yesterday I got the battery light on so checked voltage on obd fusion at idle and was 11.7... turned the truck off, with key on, 12.7... started and back to 11.7 and would go to 13-13.5 driving but back down to 11-11.7 idle...
today... no voltage drops, 12.7 before cranking, 13.5-13.8 all day idle and driving...
battery is less than 6mo old
but the light is still on. Intermittent... same as yesterday tho...
It's the crazy battery management system these trucks have. It doesn't make a whole lot of sense and it acts crazy at times. The good news is, you can unplug it and it causes no problems and the battery will function at a full charge at all times after that. The harness is about 4-6" off of the ground connection of your battery. Unplug it and it won't do that anymore. You will find lots of threads on issues like this.
Thanks!!! I had the battery tested. 8mo old and shot. Replaced under warranty and will see if it comes back after relearning process... voltage now back to 14s so I think battery was it after all.
Thanks!!! I had the battery tested. 8mo old and shot. Replaced under warranty and will see if it comes back after relearning process... voltage now back to 14s so I think battery was it after all.
Thanks again!
I had to replace my original one back in November and did the relearning process and it still kept giving me the "System Off to Save Battery" errors all the time. Went on for awhile and the battery was of course brand new. Even when I went to use Forscan it would fail because it required at least 11.5 volts and it would be at 11.4 or lower. Unplugged that stupid harness and never had a problem again.
Are we talking about the same sensor? Black connector? On the ground wire about 4-6" from the battery? It has nothing to do with starting the truck so I'm not sure why it suddenly wouldn't start.
Yup. Kinda attached to the battery box... maybe runs to the starter?
That is not the BMS hall sensor then. There are tons of folks on this forum that have long since disconnected the BMS sensor with no issues.
The only thing disconnecting it does it eliminate the "battery save" message that shuts down the radio and pops up on the screen.
My understanding is that all this sensor does is monitor battery voltage and then start shedding off electronics as the voltage drops and vehicle is not running/charging.
It doesn't even affect the charge rate of the alternator to the battery as that is managed by the voltage regulator in the alternator.
That’s strange. I’m just getting a battery icon and annoying dinging lol...
ill disconnect and monitor voltage every once in a while if the icon doesn’t go away.
You may actually have another issue based on seeing the battery icon and the dinging.
To my knowledge the BMS doesn't trigger that battery light or dinging... it just shuts down radio, heated seats..etc... any power hungry electrical components or systems.
I had seen the "battery save" message many times in the past but never the battery warning light.
04-18-2018, 01:25 PM
Battery Light on... Was thinking alternator until...
