The only way to fix it was to unplug the 12V battery for 30 seconds, and everything went back to normal. But why did this even happen?
2023 XLT ER here—this happened to me after a week of freezing temps. I left my truck unplugged, and the cold just drained the 12V. I had to ‘jump’ it, then plugged into a high-output charger for about 30 minutes. Since these trucks don’t have alternators, the best way to keep the 12V charged is to leave it plugged in when not driving. I didn’t used to follow ‘Always Be Charging’ for EVs, but now I do.
@Arin
Yeah, I think it’s just too cold out here in South Florida 
Think of it like a phone—sometimes you just have to reboot it to get it working right. The Lightning is basically a giant computer on wheels.
Orion said:
Think of it like a phone—sometimes you just have to reboot it to get it working right. The Lightning is basically a giant computer on wheels.
Maybe it fixed my screen too lol. Hate waiting 3-5 business days just to press a button and change the AC.
@Joss
Haha, I hear ya. It could be faster, but it is what it is.
Orion said:
Think of it like a phone—sometimes you just have to reboot it to get it working right. The Lightning is basically a giant computer on wheels.
You should never have to reboot a vehicle’s computer just to make it work properly. Maybe for the infotainment screen, but that’s about it.
Source: I design engine control systems.
Sounds like your 12V battery might actually need replacing.
Axel said:
Sounds like your 12V battery might actually need replacing.
The problem with these trucks is that the onboard DC-DC charger only puts out around 13.7V when driving. That means the 12V battery never fully charges to 14.5V, which leads to sulfation over time. A lot of trucks have been having AGM battery failures, especially in cold climates. There was even an old recall about this.
If you replace it, consider a LiFePO4 or sodium battery. Ohmmu makes great ones, but they’re pricey. If you get freezing temps where you live, go with the sodium pack—LiFePO4 batteries don’t charge well in the cold.
Axel said:
Sounds like your 12V battery might actually need replacing.
Not speculation—it’s almost a guarantee! Same thing happened to me. One morning, my 12V just died out of nowhere. I did see ‘Battery Saver Mode’ pop up before that, but I thought it was a new feature. Turns out ‘Battery Saver’ actually means your 12V is on its way out.
@Grier
Had a Ford tech come to my driveway last week for recall updates. He replaced my battery and said it’s normal for Lightning 12V batteries to last only 1-2 years. I’m in Arizona, so maybe the heat makes it worse. Regular car batteries here don’t last long either.
This reminds me of those old 466MHz computers where you had to push the big power button, wait, and restart because it just froze up.
Ali said:
This reminds me of those old 466MHz computers where you had to push the big power button, wait, and restart because it just froze up.
lol
Ali said:
This reminds me of those old 466MHz computers where you had to push the big power button, wait, and restart because it just froze up.
Just waiting for the boot beep… beep…
No beep? Time to restart.
Man, I miss the sound of old floppy drives spinning up and hard drives scanning that single platter.
‘You have died of dysentery.’
Mine did that the other day, but the errors disappeared after a couple of short trips.
If you’re seeing errors like this, try slow-charging at 10A for 24 hours to bring your battery back to 100%. A lot of dealership batteries sit for weeks and slowly drain. If you fast-charge instead of a slow top-up, you won’t fully recover its capacity.
Once an AGM battery drops below 10.5V, it’s hard to bring it back to full health. I’ve had my 12V replaced twice already for this reason. Before they installed my third one, I made them slow-charge it for a full 24 hours. No issues since—7500 miles and 9 months later.
@Nico
I charge at home every day, and my truck’s already at 55k miles after a year and a half.