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2024 Lariat - Heat Not Working Well

TaxmanHog

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It doesn’t but I come from a humid climate. Turn on recirculation with air conditioning on. The dryer will take the moisture out of the cabin.
Precisely the correct way to manage moisture in the cool season, most folks have been freaking out when they see the AC lamp illuminated, manually turning it off prevents the dehumidification cycle to run.
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Altivec

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Precisely the correct way to manage moisture in the cool season, most folks have been freaking out when they see the AC lamp illuminated, manually turning it off prevents the dehumidification cycle to run.
Yes, anytime you need to get rid of humidity in warm or cool weather, A/C with recirc is the way to go. Sometimes I have my A/C and my heat on at the same time. But when it drops below freezing, I don't think running the A/C is a good idea. DatOleMan said, to turn the recirc on because it takes a lot of energy to heat the cabin with outside cold air. As I mentioned, if I do that where I live (Canada) in winter, all the windows will frost up in minutes. I am pretty sure that is the reason the recirc setting doesn't stay on. They don't want people that have no clue, to all of a sudden, not be able to see out their window because someone left the recirc on.

In saying that, I hope Ford starts upping their game in software. I like Recirc on in the summer because I have allergies. It should be fairly easy for the truck to know if it's in freezing outside or not. If its not, the setting should stick.
 

Firn

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Yes, anytime you need to get rid of humidity in warm or cool weather, A/C with recirc is the way to go. Sometimes I have my A/C and my heat on at the same time. But when it drops below freezing, I don't think running the A/C is a good idea. DatOleMan said, to turn the recirc on because it takes a lot of energy to heat the cabin with outside cold air. As I mentioned, if I do that where I live (Canada) in winter, all the windows will frost up in minutes. I am pretty sure that is the reason the recirc setting doesn't stay on. They don't want people that have no clue, to all of a sudden, not be able to see out their window because someone left the recirc on.

In saying that, I hope Ford starts upping their game in software. I like Recirc on in the summer because I have allergies. It should be fairly easy for the truck to know if it's in freezing outside or not. If its not, the setting should stick.
Although cold air is more dry, you also have to replace a LOT of the warm humid air with cold dry air. It's likely far better to condition the air you have, than to exchange it with outside air.

To expand on that, if the air inside is warm and humid then they only thing you have is to exchange it with outside dry air, which you now have to heat up from whatever temp it is at (so, say -10f). Alternately the hvac only has to get cold enough to cause the humidity to condense on the heat exchanger, which only needs the heat exchanger to reach the dew point (which could be as high as +50f for an air temp of +70f). So the question becomes, what is more efficient, heating -10f air to 70 degrees, or cooling 70f air to 50f, and then heating it back to 70f?
 

Altivec

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Although cold air is more dry, you also have to replace a LOT of the warm humid air with cold dry air. It's likely far better to condition the air you have, than to exchange it with outside air.

To expand on that, if the air inside is warm and humid then they only thing you have is to exchange it with outside dry air, which you now have to heat up from whatever temp it is at (so, say -10f). Alternately the hvac only has to get cold enough to cause the humidity to condense on the heat exchanger, which only needs the heat exchanger to reach the dew point (which could be as high as +50f for an air temp of +70f). So the question becomes, what is more efficient, heating -10f air to 70 degrees, or cooling 70f air to 50f, and then heating it back to 70f?
I never thought of that. I was always told not to use your A/C below freezing because you can damage it. But I was told that for my home A/C. I just assumed that would apply to my cars A/C as well. It would make sense that a vehicle's A/C is more robust to handle extremes like that though. I would definitely need to do more research before I would attempt it.

Then there is, as you mentioned, the efficiency. Is it more efficient to heat dry cold air from outside or use the A/C compressor to condition and reheat inside air. I am thinking not because why wouldn't EV manufactures promote it as a more energy efficient way of heating the cabin. I'll have to search and see if anyones done a YouTube on this. I'll be damned if I've been heating my vehicles wrong all these years.
 

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For heat - yes, but I don’t recalll have an issue with AC. Only heat. Main thing is no heat out of front vents and not enough wind out of bottom vents. Will test tomorrow again.
 

TaxmanHog

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I created a video showing what my truck is doing, is this the same thing you notice?

Nice, your test definitely shows that cycling the air flow is not happening when we expect that it should, I personally would like to see a periodic cycling from floor to dash to window vents, that would help stir up the air in the cabin better.
 

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My Tesla will hold the fan until it heats up, then gradually phase them on. Lighting will blast the driver with cold air for 3 minutes until the heat pump finally warms up.

I've also noticed the heater is inconsistent- it blows lukewarm air, and then really heats up the cabin when the battery is preconditioning on the way to a fast charger. I'm guessing it's doing some heat scavenging from the battery when it shouldn't be.
 

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TaxmanHog

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I've also noticed the heater is inconsistent- it blows lukewarm air, and then really heats up the cabin when the battery is preconditioning on the way to a fast charger. I'm guessing it's doing some heat scavenging from the battery when it shouldn't be.
NOTE: 2022/2023 system, but I suspect the heater core is substituted for a HP condenser/evaporator .. or the entire AC/HEAT system is swapped for the HP system, but a PTC and glycol loop is still in play for battery conditioning.

I'd love to see the architecture of Fords HP system.

The glycol loop is designed such that the cabin heater core is between the PTC and the HVB when the diverter valve is set to battery conditioning sub-loop.

That ensures cabin warming happens and the battery is next in line.

Try lowering the fan to bare minimum if you get too hot.

Ford F-150 Lightning 2024 Lariat - Heat Not Working Well 1732457337240-n3
 
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rufustlong

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OP here. I checked the Lighnting rental I am using while traveling. It is indeed a 2024 XLT (2/24 build date), and has had no issues with HVAC. It is 40 degrees in the morning and 75 in the afternoon where I am at. No issues with either AC or Heat.

it sounds like I need to have the Ford dealer check out my ‘24 when I get back home.
Yeah it's certainly not ICE heat with the heat pump. You have to crank it to warm up. Utilize those heated seats and steering wheel and most importantly set a departure time (with warm setting this time of year). It heat soaks everything and makes it more of a maintenance warming instead of a large mountain to climb.

I got into the habit of plugging in everyday regardless of what is happening and even on the weekend I have my departure time set for 7:30 then I'll just modify it if I am leaving earlier or later.

Like others mentioned here using recirc enroute also helps retain the heat. After the cabin is prepared for departure I try to use auto as long as possible when range is a factor, but if it starts to get chilly at all, I'll throw the beans at it and go full on manual.
 

rufustlong

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I created a video showing what my truck is doing, is this the same thing you notice?

I agree! Auto 3 should give you the same result as cranking the manual. Would be nice if Ford updated that. We all know it means death to the battery but that would be nice to streamline the setting.
 

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I’ve noticed that my 24 Flash doesn’t like to use the dash vents for heat when on Auto climate. It seems to prioritize floor heat and windshield defrost.

I think this logic contributes to the feeling that the heat isn’t working well because you don’t literally feel it as easily. Switching to manual I can feel the heat so I know it’s working at least.
 

majerus

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Yeah it's certainly not ICE heat with the heat pump. You have to crank it to warm up. Utilize those heated seats and steering wheel and most importantly set a departure time (with warm setting this time of year). It heat soaks everything and makes it more of a maintenance warming instead of a large mountain to climb.

I got into the habit of plugging in everyday regardless of what is happening and even on the weekend I have my departure time set for 7:30 then I'll just modify it if I am leaving earlier or later.

Like others mentioned here using recirc enroute also helps retain the heat. After the cabin is prepared for departure I try to use auto as long as possible when range is a factor, but if it starts to get chilly at all, I'll throw the beans at it and go full on manual.
Might be worth trying a similar test to the one i did. From my truck, its not a heat problem its rather no volume of air is actually moving the heat into the cabin. That bottom vent in my video is like 150 degrees, and my feet will still cold. (also took 20 mins to warm the cabin.)
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