Drive mode not available

[PatagonianMara]

follow-up: the dealer found my 12V battery had low voltage and replaced the battery. This brought back my drive modes. They replaced the 12V battery under warranty. It's hard to believe a well-designed system would eat through a normal lead-acid battery in under a year.

I had an additional problem with my display overheating. During a hot day, doing navigation, with no air conditioning, the screen was uncomfortably hot to touch. I couldn't believe computer equipment could get that hot without self-destructing. There were sensors that registered numerous DTC fault trigger conditions with the display. Were these also do to the low voltage battery? The dealer mechanic could not reproduce.

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[PatagonianMara]

Further follow-up: The drive mode problem is most likely indeed due to a low SOC on the 12V battery.

It started happening again with the new battery, and I charged the 12 V with a NOCO Genius trickle charger, and the problem went away.

The problem doesn't seem to really be related to heat or needing a new console shift lever.

That dinky little 12V battery wears down so quickly.

I don't drive my truck much, so I need to keep a close eye to charge that battery.

A lot of stuff is going on even while your car is just sitting.

 

[Adventureboy]

If you have an OBD2 reader, you can check your Quiescent amperage. This tells you what the truck draws from the battery on average in standby mode after everything shuts down. It should be between 30mA and 50mA for our trucks if everything is normal. If it is higher than that, you might have parasitic draw somewhere causing you grief, and it might warrant further investigation.

If you don't drive on a regular basis, some of us have permanently installed a battery maintainer to keep the 12v from cycling as often. In my case, I also upgraded my battery to H4 for some additional capacity in the last round, but that took a small bit of work on the battery tray to get it to fit.

 

[PatagonianMara]

good points. I do have an OBD2 reader and I have not looked into that feature. I should.
Another thing though is that reader will not capture rare events like software downloads. Will upgrading the battery to H4 or something even larger cause problems with the software in the car? 12V is 12V, but the software may be expecting a different capacity when it is trying to manage it.

 

[Adventureboy]

Will upgrading the battery to H4 or something even larger cause problems with the software in the car? 12V is 12V, but the software may be expecting a different capacity when it is trying to manage it.

There are no issues. I've monitored the 12v process in the truck for about 3 years. The larger H4 gets charged the same as the H3, it just cycles much less often and the BMS carries on.

Not sure on your 2024, but much more modification would have been needed on my 2023 to fit anything larger than an H4. Not impossible, but I'm not sure anything larger than an H4 is needed unless you are trying to run aftermarket accessories from it. The truck charges the 12v from the HVB when it drops below about 50% SOC, so the H4 cycles fewer times.

 

[Dan C]

I had the no drive modes when the truck was new, it hasn't happened in a couple of years. I had a low battery this year but that fault did not return. The dealer charged my 12v battery and said it was fine. I replaced it anyway with an H-4.

 

[PatagonianMara]

Found this from AI:

Dimension	H3 (BCI Group 153R)	H4 (BCI Group 140R)	Dimensional Difference
Length	6.94 in (175 mm)	8.15 in (207 mm)	H4 is 1.21 in (32 mm) longer
Width	6.94 in (175 mm)	6.89 in (175 mm)	Identical (0 mm variance)
Height	7.50 in (190 mm)	7.48 in (190 mm)	Identical (0 mm variance)

Tray Compatibility: Many modern electric vehicles (like the Ford Mustang Mach-E) ship with an H3. While their physical trays sometimes include secondary bolt holes to accommodate the longer H4 size, upgrading isn't always recommended unless the vehicle's Battery Management System (BMS) can be reprogrammed to handle the extra capacity.

1. Physical Modifications (Plastic Tray Surgery)
The H4 battery will not drop directly into the 2024 F-150 Lightning's stock plastic battery tray because of its extra 1.21 inches of length.

• The Mod: Lightning owners upgrading to an H4 typically have to perform "light surgery" on the tray. Using a Dremel or an oscillating saw, you must trim away 8 to 9 plastic alignment ribs/fins on the sides and back of the tray.
• The Fit: Once those plastic tabs are cut flush, the H4 battery slides perfectly under the rear firewall ledge, and the factory front hold-down clamp will bolt right down normally using your standard 8mm socket.

2. The Battery Management System (BMS) Debate
Your truck's internal charging computer is explicitly programmed from the factory to manage a 35 Ah H3 battery.

• The Risk: Some automotive technicians note that because the BMS expects a smaller capacity, it may undercharge an H4 battery over time, potentially shortening the new battery's lifespan.
• Community Consensus: Despite this, many real-world Lightning owners report that the truck's charging is heavily voltage-based. Upgrading to an H4 successfully stops deep-sleep errors because the baseline capacity is so much larger (50 Ah vs. 35 Ah).

3. Essential Step: Performing the Manual BMS Reset
Whether you stick with a direct-replacement H3 or modify the tray for an H4, you must reset the truck's Battery Management System immediately after installation so it knows a fresh battery is present. You can do this right from the driver's seat without special tools:

1. Hop in the truck and press the Start button once without touching the brake pedal (putting it into Accessory Mode).
2. Flash the high-beam headlights using the steering column stalk exactly 5 times.
3. Press and release the brake pedal exactly 3 times.
4. Watch the driver's dashboard; the battery icon will flash 3 times, indicating a successful system reset

Some extra tips folks may or may not be aware of:

no, you should not perform a manual BMS reset if you are just recharging your existing battery with an external charger.
The Battery Management System (BMS) tracks the overall age and health degradation of the battery. You should only reset the BMS when you physically replace the old battery with a brand-new one. If you reset it on an old, charged battery, the truck will mistakenly treat it as brand new, which can lead to overcharging and premature battery failure.
Instead of a reset, you just need to let the truck naturally calculate the new state of charge by following the correct connection steps:

1. Connect to the Correct Ground Point
When attaching your external charger, do not connect the negative (-) clamp directly to the negative battery terminal.

• Why: Connecting directly bypasses the truck's BMS sensor (the small ring attached to the negative terminal). The truck will not realize energy is being added.
• The Correct Way: Connect the positive (+) clamp to the positive battery terminal, and the negative (-) clamp to a bare metal ground point on the vehicle chassis away from the battery. This forces the charging current to flow through the BMS sensor, allowing the truck to track the incoming power.

2. Let the Truck "Sleep" to Re-calibrate
Once your external charger indicates the battery is fully charged, disconnect the charger, lock the truck, and let it sit undisturbed for at least 8 hours (ideally overnight). During this quiet period, the truck’s modules go into a deep sleep and automatically re-evaluate the battery's resting voltage, updating the state-of-charge calculation on its own without losing its history of the battery's age.

 

[Dan C]

The lifespan couldn't be much shorter.

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