Heat Stopped Working

Subject kinda says it all, blows cold air only. Worked one day then not the next. I'm bringing It to the dealer but thought I would check to see if this was a common problem with anyone else. I had the wiring harness repleaced last month due to SSN code. Anyone have thoughts? It's been cold this week!!

Did you check the fuse? I've actually thought of taking the fuse out in the summer to ensure the heater doesn't come on if I turn the temp up a little while running the AC.

davideos said:

Did you check the fuse? I've actually thought of taking the fuse out in the summer to ensure the heater doesn't come on if I turn the temp up a little while running the AC.

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They should have a master heater off setting to do that!

Well that's a novel idea. I will check the fuse - I should have come up with that on my own. And I don't mean to sound sarcastic, I truly feel like a bit of an idiot that I didn't come up with that on my own...

EDIT - so after a bit more research, the cabin heater is considered high voltage, which requires the large battery to be disconnected before it is replaced. This is certainly not something I'm going to attempt on my own so i guess it's back to the stealer. Kinda bummed that I can't self diagnose this. Gone are the days when you can fix things on your own.

jwilson165 said:

EDIT - so after a bit more research, the cabin heater is considered high voltage, which requires the large battery to be disconnected before it is replaced.

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The cabin heater fuse, you mean?

I'm not sure you need to disconnect the HVB just to check the heater fuses and/or relays (in the front fuse box). I could find no warning against doing so in the manual.

Of course, as you would when working with any fuse, make sure the car is off (and, in the case of the FFE, not charging). This will ensure that the high voltage battery relays are disengaged (you can even hear them disengage as you turn off the car). While not truly the same as being physically "disconnected", no current should be flowing through the heater-related fuses.

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EDIT: Okay, I did find a warning. Yeah, probably safe to take it to the dealer.

I guess if you wanted to be belt and suspenders safe, you could pull the battery disconnect in the rear seat.

Wouldn't be a bad thing to know how to do that anyway Jwilson - in the event that you have an accident, the fire department likes to know how to disconnect the battery.

Ok, so first super cold day of the year today in Chicago (car said -2), and I think I am having the same issue. I am getting some warm air (enough to keep the car defrosted) but it's not as hot as it usually is. What do you think could be causing this?

Yesterday it was about -5 here when we were out and about. Even after remote starting the car for 25 minutes before we left the car was not very warm after being parked outside for a few hours. The entire time driving we left the heat set on Auto at 75 F and the air blowing out of the vents was barely warm and the dash showed 5+ kW of use the entire time, we never saw it drop below 5+ kW. We burned through over 80% of the battery driving about 20 miles total yesterday. A trip that takes 1.2-1.3 kWh in the summer with A/C took 3.3 kWh yesterday.

I don't think that anything is wrong with the car, I just think that its heat cannot handle our cold winters. Even ICE vehicles can produce limited heat in this weather or can never really reach operating temp when it's so cold. This morning it was -12 when my wife dropped me off at work on her way to work. Since the car was parked underground overnight and preheated to 85 F using a Go Time it was nice and warm for the first few minutes. It'll be interesting to see how warm the car is when she picks me up this evening.

hybridbear said:

The entire time driving we left the heat set on Auto at 75 F and the air blowing out of the vents was barely warm and the dash showed 5+ kWh of use the entire time, we never saw it drop below 5+ kWh. We burned through over 80% of the battery driving about 20 miles total yesterday. A trip that takes 1.2-1.3 kWh in the summer with A/C took 3.3 kWh yesterday.

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Actually that is 5kW+, not kWh. The Climate and other meters show kW values not kWh.

jmueller065 said:

hybridbear said:

The entire time driving we left the heat set on Auto at 75 F and the air blowing out of the vents was barely warm and the dash showed 5+ kWh of use the entire time, we never saw it drop below 5+ kWh. We burned through over 80% of the battery driving about 20 miles total yesterday. A trip that takes 1.2-1.3 kWh in the summer with A/C took 3.3 kWh yesterday.

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Actually that is 5kW+, not kWh. The Climate and other meters show kW values not kWh.

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You're right. I'm so used to typing kWh that my fingers did it without thinking... those displays show a level of instantaneous power (kW), not a rate of consumption (kWh). I fixed my post now.

I ran into this last winter as well. Turn recirculate on until the cabin warms up. Then when you reach temp and if the windows start to fog, you can turn recirculate back off.

hybridbear said:

Yesterday it was about -5 here when we were out and about. Even after remote starting the car for 25 minutes before we left the car was not very warm after being parked outside for a few hours. The entire time driving we left the heat set on Auto at 75 F and the air blowing out of the vents was barely warm and the dash showed 5+ kW of use the entire time, we never saw it drop below 5+ kW. We burned through over 80% of the battery driving about 20 miles total yesterday. A trip that takes 1.2-1.3 kWh in the summer with A/C took 3.3 kWh yesterday.

I don't think that anything is wrong with the car, I just think that its heat cannot handle our cold winters. Even ICE vehicles can produce limited heat in this weather or can never really reach operating temp when it's so cold. This morning it was -12 when my wife dropped me off at work on her way to work. Since the car was parked underground overnight and preheated to 85 F using a Go Time it was nice and warm for the first few minutes. It'll be interesting to see how warm the car is when she picks me up this evening.

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Are you sure your remote start function was set to warm the cabin? Once in awhile I've seen that setting change without a reason. Was your drive very short? If it was a drive that uses up 1.2kWh, I'd guess it was only 5 miles or so - so if it only took 5-10 minutes, maybe it didn't have time to warm the heater elements?

If the remote start was set properly and you were driving for more than 10 minutes, I would not assume this is typical FFE cabin heater behavior in single digits or even down to -15 like we had last winter. Yes the heater eats a ton of juice, but it gets the job done. I park in a detached unheated garage at home. This morning (-2F) my go time 85F felt as warm as it does when it's 30 out. Well, felt warmer if anything, compared to the ridiculously cold air outside. I only lasted 5 minutes before I needed to turn on the heater again for my drive, and it kept me comfy at 67 for the 40 minutes remaining. I parked street side at work, leaving for kid's school around 8 hours later when it was a balmy 6 degrees outside and inside my car. Cabin warmed up to the mark in about maybe 6 minutes.

Jmueller, Eva, Jeff, other Midwesterners- feel free to chime in, you guys didn't have trouble with the heater's performance last winter, did you?

My main issue is fogging/frosting. Especially when I have passengers, which is most of the time, side windows fog in cold/frost in freezing weather, even if I'm using cabin heater.

Anyway, if it seems anemic, sefs' suggestion is good. But I've seen a few posts over the past few winters where owners have needed their heater replaced/repaired. One was not too long ago, wasn't the owner's heater working but the pump broken, so it showed energy draw but blew cold air? Maybe I'm imagining things.

dmen said:

Jmueller, Eva, Jeff, other Midwesterners- feel free to chime in, you guys didn't have trouble with the heater's performance last winter, did you?

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Aside from it occasionally skipping a go time, no....until today

As usual for these frigid days (car said 10F on the way in) I also have the go times set for 85F. Unfortunately for me, today the car decided to do a really funky thing: It preconditioned the cabin, but used the HVB to do so (it was still plugged in for its overnight charge) and it wasn't very warm at all making for a very frigid commute. In addition I started out with 92% battery instead of 100%. The result of this was I didn't run the heater at all on my way in other than the seat heat--I'll try it on my way home (may even setup a go time for later this evening to see if it warms up).

This was the oddest behavior I've seen yet for the car.

I'll throw out another possibility. Your battery was cold. From my experience with other Li-ion batteries, below about 32F available current output falls off a cliff. I used a Lithium starting battery on my motorcycle. In extreme cold the battery would act like it was dead and unable to start the engine yet it would power the lights just fine. in upper single digits I could barely get it to start after about 5 minutes of trying to crank the engine. I only tried below zero once (-13F). I could not get it to start and gave up after 5 minutes when my fingers started to freeze. Based on that experience I would not be at all surprised to have problems with our cars in single digits or below especially if your car has set unplugged in sub-zero temps for an extended period of time.

The car wasn't frigid cold, it just wasn't warm like usual. Often we will start out leaving home with the car pre-conditioned to 85 and we don't hardly need any heat then. Later on in the day after it has sat we can usually remote start with the climate set to auto and the car will be pretty warm inside after 15 minutes. Then driving home with the HVAC set to 67-72 depending on how cold we are the HVAC demand will alternate between 5+ and 0 kW, occasionally showing 1-3 kW of power demand. The car gets quite warm and we usually are turning down the temp as we drive. On the frigid day the interior temp never felt like it got above 40 F. Last night when my wife picked me up it was similarly cold inside the car.

I don't doubt that the battery is cold after sitting out all day. At night it should warm up from charging and from being parked in a heated garage.

I don't think anything is wrong, I just think the electric heater can't keep up with this cold weather.

The previously mentioned trip is 6.3 miles and usually takes about 12-15 minutes depending on the timing of the traffic lights. In the summer it takes 1.2-1.3 kWh although we have seen trips show 1.1 kWh. Even with A/C running we didn't use more than 1.3 kWh according to the car on that trip. Remember that 1.3 on the display means anything from 1.30-1.39999999 kWh (the car measures to 8 decimal places).

No problems here with the heater keeping up in cold weather. Yesterday it was 9 degrees outside. Not heated garage, go times set to 65 degrees, car starts out toasty warm fine. Sat outside all day at 9 degrees. Car got warm inside with no problems - run it at 64 degrees auto. As always, frosting windows is a problem.

Yeah the car is down to about 50 miles GOM range now. But then the round trip commute is only 24 miles - so it works just fine.

Honestly, the FFE and Tesla both get warm so much faster than an ICE. I love that the car isn't sitting there idling an engine to just warm up the car. I see cars warming up and just think about what a waste that is.

And both cars have trouble with frosted windows and passengers. It just seems to be the nature of the beast.

EVA said:

And both cars have trouble with frosted windows and passengers. It just seems to be the nature of the beast.

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Yeah and to think Ford has this in the parts bin (and available in Europe for the Focus) so the engineering to include it on the FFE would be very minimal:
https://www.youtube.com/watch?v=BmpROemcd4E

jmueller065 said:

EVA said:

And both cars have trouble with frosted windows and passengers. It just seems to be the nature of the beast.

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Yeah and to think Ford has this in the parts bin (and available in Europe for the Focus) so the engineering to include it on the FFE would be very minimal:
https://www.youtube.com/watch?v=BmpROemcd4E

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Yes, it is almost criminal that Ford won't offer this and a heated steering wheel on the FFE. I wouldn't expect theses items to be standard equipment as they would raise the base MSRP but as cost options they would really improve the FFE viability in cold winters. I expect that most people here would pay for them as part of a "winter equipment package"! Ford why are you not listening to your customers or at least not acting on their requests?????