Frunk alarm triggered at 3am

[hammer thumb]

After this happened 4 times I was sure there was a faulty something and no intruders. To the delight of my neighbors, I started parking in the garage and left the doors unlocked. My dealership wants me to leave the truck 2-3 days for diagnostics. Fortunately, it’s still under the bumper to bumper warranty. On my Ford phone app, I got the attached message. I love this truck but WTF? Has anyone experienced any frunk alarms issues? It’s mechanically latching properly and all the body lines are parallel and straight. Dealership has no clue. Looking for help. Thanks.

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[fhteagle]

How fresh is your 12V battery ?

Mine did a nuisance frunk alarm twice with the old 12V, but has not done it since I got a fresh one.

 

[chl]

Agree with the 12v battery as the usual suspect.
When weak it off-loads various things leading to false alarms and malfunctions.
If it is the 12v battery, after you get a new battery, put it on a maintainer with an AGM mode like many of us have done - see the various forum threads, e.g.:

https://www.f150lightningforum.com/forum/threads/charging-12v-battery.16979/

One caution about having it in a garage with a weak battery, I believe one or two of us have had our Frunk open on its own likely when the 12v battery got too low.

Also if the 12v gets too low and you need to jump it, you'll need to open the Frunk manually inside the garage to get to the battery compartment and a jumper long enough to reach possibly from outside the garage.

 

[hammer thumb]

Yeah, I was thinking maybe it's the 12 V battery issues. But then again, I've been tough on my front because I keep all my tools there and I added a soft topper in the back so I thought maybe that all the alarms were related to something I had done. The dealer wanted to have the truck for three days. After tracking the alarms on my phone app and get a minimal information back from the dealership, I went to pick up the truck and the dealer said it looks like it's your 12v battery, but it need to fail twice in order for it to be covered under than the bumper-to-bumper three-year 30 K. So the dealership wants me to bring the truck back for another three days and I'm just thinking why don't I just put a new battery in? Dealer said no that won't work because they have to calibrate the battery monitor software whenever you change the battery. Is that true? I thought I'd read many people are just swapped out their own 12 V battery moved on and all was fine. Dealer also told me you can't unplug the battery and plug it back in without messing up the software? I was under the impression that was a simple reboot of the whole system. Is the dealer blowing smoke out their tail pipe ...? Ha

 

[chl]

Yeah, I was thinking maybe it's the 12 V battery issues. But then again, I've been tough on my front because I keep all my tools there and I added a soft topper in the back so I thought maybe that all the alarms were related to something I had done. The dealer wanted to have the truck for three days. After tracking the alarms on my phone app and get a minimal information back from the dealership, I went to pick up the truck and the dealer said it looks like it's your 12v battery, but it need to fail twice in order for it to be covered under than the bumper-to-bumper three-year 30 K. So the dealership wants me to bring the truck back for another three days and I'm just thinking why don't I just put a new battery in? Dealer said no that won't work because they have to calibrate the battery monitor software whenever you change the battery. Is that true? I thought I'd read many people are just swapped out their own 12 V battery moved on and all was fine. Dealer also told me you can't unplug the battery and plug it back in without messing up the software? I was under the impression that was a simple reboot of the whole system. Is the dealer blowing smoke out their tail pipe ...? Ha

If you put in a new battery with the same exact parameters as the OEM (35AH, 380CCA, 60RC AGM) then you just have to do the BMS reset:

LVB BMS reset

Make sure 12v battery is fully charged (drive an hour, or after an hour actively charging the HVB)
Start Accessory mode
flash high beams 5 times
step on brake pedal 3 times
red battery icon on dash should flash 3 times

Even the dealership would have to do that when they put in a new battery.

Just remember it is an H3 size battery so if you get a larger footprint one, you'd have to modify the tray.

Some have done that - search the forum and you'll see how to do that.

Beware a Ohmmu replacement - there have been some issue with them which a search will uncover.

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