Hot footwell / feet issue 2019 model 3 LR.

[Gyrolion]

This past week I had a longer roadtrip and on my way home I started to encounter very hot feet.
So it might be that I was excited to drive but in reality the HVAC was cranking up the heat to the lower part of the car like crazy, while it was blowing cold air in the upper parts. So my body was kinda cold but my feet where very hot.
I'm on one of the latest software versions so that is nog a issue.

So after some googling I found out I'm not the only one with the same problem, except it has been very quiet for half a year (no winter, only summer) so now the temperatures are dropping again are more people having the same issues with hot feet and cold body's?
Or did Tesla do an upgrade and I might have a faulty sensor?

See this video for an explanation of the problem:

 

[Gyrolion]

This seems to be a common issue, or a resolved one... but not for me so I do have a service appointment next week, I put it on the list of things the service center must look at.

 

[Gyrolion]

Well since this post does got some views, but no reply's I will report back.

Went to the SC and the did reproduce the problem, but the stated it is a known problem and should be solved by a upcoming software update sometime...
But the coulden't tell me when the software update would come. I wonder if it will ever come because this issue seems to be ongoing since the release of the model 3.

So basicly having toasty feets and also rear passengers because those vents spew out hot air as well if normal for a Model 3 pre heat pump...

I hope I'm not the only one with the problem.. but by the lack of reply's I think I'm...

 

[Phlier]

I've been following this particular problem here on TMC since it was first reported. Read a ton of posts/threads about the issue.

This is all just my opinion, based on what I've read...

IMO, Tesla has a QC issue on a few of their HVAC components (most likely thermistors or thermocouples) that control how the air is mixed (what vents it blows out of).

For those people that were able to get their problem fixed by an SC, the SC replaced the parts in question.

For those that haven't been able to get it fixed, it's because the problem part(s) are still "within tolerance;" that unknown range of value(s) a part can be in and not be eligible for replacement. Rather than telling their customers this, they pawn it off to the "oh yeah, we'll fix this in a firmware update" crutch.

Unfortunately, I don't see Tesla doing anything about this since it effects a relatively small amount of the fleet.

My July 2019 Model 3 (stealth) Performance hasn't had it.... yet.

One thing that strikes me as particularly odd... when an SC has been able to fix the problem, they've left the actual fix off of the invoice, including any parts (and their associated part numbers).

It would be great if those that were able to get an SC to fix the problem would post their invoices showing any corrective action and part numbers. Actually, just posting the repair invoice in all circumstances would be useful, as even posting one that doesn't show what corrective action was taken or part numbers is still useful.

 

[Stampee]

I have the opposite problem. My feet are always cold. I crank the heat up to high, my body and head are roasting, yet my feet are still cold.
Stampee

 

[Gyrolion]

I have the opposite problem. My feet are always cold. I crank the heat up to high, my body and head are roasting, yet my feet are still cold.
Stampee

Very strange that you have the complete opposite problem, but that is a problem that I would love to live with. The hot footwells are not fun at all.
What year and month is your model 3 from?

But I made another service appointment, when the are going to call me that it is a software issue, I gonna ask them to replace the temperature sensor.. (if the dont wanna do it on warrenty it will be on my costs) hopefully I will then get a newer one with the grill, the got a pump inside of them the draw in fresh air.
It is atleast worth a try and the most easiest thing to get replaced.

I will report back in due time.

 

[Stampee]

Mine is a 2021 model 3 refresh. I picked it up december 21, 2020

 

[Gyrolion]

Well, I got called because of the second service ticket by a different SC and I was expecting a call saying it is a software thing.
But instead the want the car ASAP because the think 50°C air hitting your feet is not normal operations for the HVAC unit.

So tommorow it is going back to the SC for only this problem, and the give me a loaner in the meantime, so the are gonna spend some good time on it.

I asked them what can possibly be wrong because another service center was talking about a software update, and he said it might be the humidity sensor but he was more aiming for some faulty HVAC valve/controller... I will report back and hopefully I can get some good information out of this.. but it can also be a let down if the can't find anything.

 

[Goose66]

I have this same problem, but just on long drives (2018 M3 LR). I was assuming it had something to do with battery management because it only happens when outside temperatures are below 50F and the car is preconditioning the battery or just after charging.

 

[Gyrolion]

The HVAC in the older model 3's has no connection to the battery that I'm aware of, except for the AC to cool the battery.

The working in my optic,

( Tesla Model 3 Teardown: Interior, and HVAC system - MarkLines Automotive Industry Portal )

Fresh air comes into the HVAC unit trough the air filters.
2 air streams go from there, one to the AC and one to the PTC heater.
Those streams are controlled by 1 main fan.
And from there the 2 streams get distributed into the cab trough a few lines/vents. Probably controlled by valves or something..

The battery is getting warmed up by stators in your engines that in turn warm up a coolant stream going trough the battery and back in the stators, including its own vessel "Superbottle". To cool the battery the AC is used. So heating up your cabin with the battery does not seem like an issue.

The new model 3 uses a heatpump that uses battery heat to somehow turn that into heat for the cab.. magic?

Please correct me if I'm wrong.

 

[Goose66]

I guess I was thinking more heat intrusion into the footwell from battery - not necessarily coming from the climate control system. So the footwell air is blowing and the heat is coming from the battery, and therefore it feels like climate control is putting too much heat in the footwell.

 

[Gyrolion]

A, well that is not an issue as well I think. Because when I start up the rear vents/footwell vents, the first minute is cold air before the heater kicks in, if its battery induced heat it should get heated instantly.
Also when I feel the floor when I'm driving a long way or when supercharging I do not feel alot of heat coming into the cabin from the battery.

 

[Gyrolion]

Well I'm back from the SC appointment, the first tested another temp sensor, and the same thing happend so that was not the problem.

The did all the test and the system worked like it should be.

But what the did find out was that a setting of the PTC heater was wrong. The changed that and now the footwells are much more comfortable! The temp overal is much more comfortable in the cab.
So I think the have fixed it, the did mention that in the future there will come a software update to handle the temps better, but this is as best as the can make it for now.

But I'm happy! The rear seat passengers will be as well because the are also not getting sandblasted by a hot stream anymore!

On a side note, the ride back was 30 wh/km (50 wh/mile) more efficient then the other way around.. while i drove faster...

 

[medphys3]

“But what the did find out was that a setting of the PTC heater was wrong.”

Can you elaborate on this? Is there a line item on the invoice that actually states what “setting” was changed?

Also- are you all in Auto or manual mode?

 

[Gyrolion]

“But what the did find out was that a setting of the PTC heater was wrong.”

Can you elaborate on this? Is there a line item on the invoice that actually states what “setting” was changed?

Also- are you all in Auto or manual mode?

Sorry no information about that, this is what the invoice said:

“changed PTC heater configuration in the vehicle configuration. This should make the drivers footwell be colder. Advise to the customer to test if the conditions have been improved. Also upcoming Firmware updates should make the conditions better. there is nothing we can do further on this issue, all systems are in a good shape and all tests passed mobileAppActivityDetails symptomKey: heating&AirConditioning activityType: COMMON”

I’m running the hvac in full auto mode now and air getting send to the footwells and rear of the cabin still has a normall temperature, instead of freaking hot.

 

[KenC]

When you get to be old, you might like that hot foot heater! I came back from skiing today, and was thinking about this thread, and how I could use that hot footwell, just about now.

 

[medphys3]

…I’m running the hvac in full auto mode now…

Sweet. Full auto is way more fun then semi auto.

 

[Big Earl]

Well since this post does got some views, but no reply's I will report back.

Went to the SC and the did reproduce the problem, but the stated it is a known problem and should be solved by a upcoming software update sometime...
But the coulden't tell me when the software update would come. I wonder if it will ever come because this issue seems to be ongoing since the release of the model 3.

So basicly having toasty feets and also rear passengers because those vents spew out hot air as well if normal for a Model 3 pre heat pump...

I hope I'm not the only one with the problem.. but by the lack of reply's I think I'm...

Same problem on both of my 2018 Model 3s but one is noticeably worse than the other.

 

[medphys3]

FYI- I have a service appointment on Wednesday for a windshield replacement. I asked them if they could look at my heater settings so the floor vents weren’t so darn hot and they said they would. Will update.

 

[DrHouseDK]

The SC here in Denmark looked at this issue yesterday. Got the following note on the service sheet:

"PTC heater rod control enabled"

No idea what this means, except my feet feel even warmer now. They told me to get back to them if it didn't get better from this. March 2020 TM3LR.