Model Y

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DANGEROUSLY inadequate windshield defrost on MY

Admittedly there have been frigid temperatures in the Midwest (below 10 degrees as a high), but it looks like I’m stuck 600 miles from home on a road trip to test out my new 2021 MY. The defrost seems to clear the windshield when I have the car still on the charger and warming up before I start to drive. However once I’m on the expressway going 50-60 mph, the windshield slowly and steadily ices up. The car keeps warm, but when I put on the front defrost is seems like the air is cool and it doesn’t clear the ice. I have to stop every 15-30 miles to scrape. Very dangerous.

Comments

  • You do know there are 2 modes when you activate the windshield defroster right? The first touch will light it up in blue which is cold air, the second touch is red which is hot air. ;)
  • First touch on defrost button is blue and cold. Second touch is red but for me not any warmer than blue and did not clear ice. Again, under 10 degrees so extreme conditions, but my advice to anyone else considering an extended road trip is to hold off if temperatures are expected to be below 15 degrees.
  • Something is wrong with your car. I consistently pre heat my car at work as it is parked outside, turn on the heater and defrost and set front drivers seat to level 2. Toasty warm when I get in and never any snow or ice on the windshield. Never had an issue even in -20 temps on the road except 1, wipers ice up easily on this car.
  • Our recent temperatures are ranging from -10 to 0 degF and I noticed that the heater system does have a hard time maintaining the cabin temperature during the drive that I would have preheated to before driving. I never had the icing problem, but I probably also didn’t have the conditions to ice, as it has simply been very cold and dry.

    I preheat my cabin to 70degF, well in advance, to make sure that cold battery icon also disappears. No problems there, hence I know the heater works. During the drive though, at these cold temperatures, I check the cabin temperature on the app, and it shows down to 50s to 60 range. I keep the climate control on auto and can feel the warm air coming out very slowly. If I manually increase the fan speed, the air simply blows colder. I’m guessing at these temperatures, we are simply maxing out the heat pump’s ability to extract heat from the outside air, especially while driving. On my 30 mile daily one way drive, and with seat heaters, it doesn’t seem to bother me, but I don’t know how it would be on a long drive.

    I am also curious to hear others’ experiences on cabin heat at very cold temperatures, to better understand whether that’s normal, or something I should get checked.
  • @MYP_in_cold

    My experience (when my heater was working, it is now broken and needs to get serviced) is that the heating system in the Y was quite weak, but acceptable. I also was reluctant to blast the heat as that can have a major impact on battery use.

    If cold air is blowing, you might have a well-documented issue with a failing heat pump - this put me in a dangerous situation a few days ago. There are numerous posts on this topic in this forum.
  • This happened to our Model Y yesterday and today. I'll contact support to figure out why. The temperature was 10 degree yesterday. When my wife drove our model Y from office to home, AC didn't heat up and the windshield became very foggy. She had to stop at the shoulder of the freeway. After she stopped the car, AC started working and fog on windshield was quickly cleared, but when she backed to traffic, AC stopped working again with cold air blew out from vent. This happened again this morning. Climate control worked before she got into the car, but when she started to drive, it stopped working again. It's extremely dangerous to stop at freeway's shoulder to wait for AC clean the fog.
  • > @MYP_in_cold said:
    > Our recent temperatures are ranging from -10 to 0 degF and I noticed that the heater system does have a hard time maintaining the cabin temperature during the drive that I would have preheated to before driving. I never had the icing problem, but I probably also didn’t have the conditions to ice, as it has simply been very cold and dry.
    >
    > I preheat my cabin to 70degF, well in advance, to make sure that cold battery icon also disappears. No problems there, hence I know the heater works. During the drive though, at these cold temperatures, I check the cabin temperature on the app, and it shows down to 50s to 60 range. I keep the climate control on auto and can feel the warm air coming out very slowly. If I manually increase the fan speed, the air simply blows colder. I’m guessing at these temperatures, we are simply maxing out the heat pump’s ability to extract heat from the outside air, especially while driving. On my 30 mile daily one way drive, and with seat heaters, it doesn’t seem to bother me, but I don’t know how it would be on a long drive.
    >
    > I am also curious to hear others’ experiences on cabin heat at very cold temperatures, to better understand whether that’s normal, or something I should get checked.

    I have had the same problem when driving after being parked outside in cold temps, even after preheating. I reported to Tesla Service and was scheduled for an appointment but at the last minute they said logs showed normal ops and there was no need to bring the car in. As I understand the way the heat pump works on this vehicle, below -10C/14F it draws heat from the battery to heat the cabin. This is why the number of regen dots can increase as you drive. I don't know whether this is supplemental to using exterior air as a heat source, or if it switches over completely. Anyway, it looks like preheating/preconditioning will be very beneficial in these conditions as it adds heat to the battery coolant that can be drawn on later.

    My big complaint is that the footwell heat is inadequate and there's no effective way to boost it. If I select dash vents off (who needs those in winter anyway, except if your hands are cold?) the footwell gets even cooler, and I have to increase the selected temperature several degrees just to stay comfortable.
  • @WattsappMTL
    What you are saying about the heat pump utilizing heat from battery coolant at cold outside temperatures makes sense. I did not know that. I do observe the regen dots increase as I start driving, even after preheating. Nowadays, my drive speed is also lowered down to 50s from its usual 60-65 mph, due to snowy roads, and hence slower traffic. I suppose this further negatively impacts the heat pump's heating ability with cooler battery due to less current flow through, and not needing as much battery coolant heat extraction, which further reduces the available heat that the heat pump can extract from the battery coolant.
  • @modelyowner
    Thank you. I will search the other posts as well. Best of luck with the repairs for you. Hope they fix the problem once and for all.
  • Interesting! In my younger days we put radiator flaps on to stop airflow through the diesel engines coolant system. This raised the coolant temp and helped provide hot air for the windshield defroster, which never did to seem to clear my windshield very well. Lot of wind moving through those old cabs. Wonder if that practice of limiting wind flow over the Tesla cooling system would help you guys. Can anybody out there with experience lay a little positive on their negative situation?
  • https://www.foxbusiness.com/energy/tesla-ceo-elon-musk-slams-texas-energy-agency-as-unreliable
  • Unbelievable. @Kyvapper is another candidate for the Darwin Award. You actually thought it was a good idea to go on a 600 mile road trip in -10 degree weather just to test out your new car? During a pandemic?
  • Don’t necessarily appreciate @NorthBay’s snide comment but unfortunately that is where forums typically devolve nowadays instead of constructive conversation. It was less than 10 degrees, not minus 10. Also to be clear, when I first embarked on my trip it wasn’t necessarily forecast to be quite that cold. But in any event I suspect that many fellow Tesla owners, like myself, still take for granted ICE features like heat and defrost that are not so straight forward in EVs. The purpose of my post was to provide warnings for others and also to see if others were experiencing similar situations. Fortunately there are constructive posts that I have appreciated.
  • And you still think it’s dangerously inadequate?
  • Here’s a more useful warning. FOR FUTURE BUYERS OF ANY VEHICLE.

    I strongly recommend you do NOT take a brand new vehicle on a long road trip with less than 2000 miles on it. Most issues will arise within the first few thousand miles.

    Especially in cold temps with a vehicle that received a batch of bad sensors.

    If you MUST take a road trip. Be well prepared.
  • I also recommend thoroughly cleaning the inside of all your windows.
    I "cleaned" mine somewhat yesterday, and while driving this morning, it was very foggy inside on the places I missed. Must now go do a better job!
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