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Model S HVAC issues

mymagiccarpet

Member
Apr 11, 2019
176
405
California
Has anyone encountered this issue?
All of this happens on auto mode, in single temp operation. All windows are tinted including the roof, and I have the mesh roof cover.
When outside is 75-85F, setting AC to 70 makes me freezing in the car. However, if outside is 90F+ and car has been driven or was sitting outside for some time, setting AC to 70F, does not cool the cabin. Cold air is coming through, but at a very reduced rate - just feels very stingy. On the top of that, at one time when it was 95ish outside, since I couldn't get any cold air, I used manual mode and set it to 11. The car actually reduced the fan on its own to 7 or 8. So essentially, to get proper cooling, you have to either change fan speed or set temp really low, but even that sometimes may not work b/c car will override it.
When using heat, it warms the car fine, but eventually it will start to blow cold air to the point where you are freezing. The only way to get warm air is to increase the HVAC temperature, and you can keep doing that until you hit HI. Interestingly, often the front right vents will blow cold air while the left will blow warm. Eventually, both will blow cold air - not particularly useful when outside is 40F.
SC cannot find anything wrong. They say they run the test, but it seems more like they turn it on once and check. Or don't. This is such consistent behavior that it's impossible to not see/feel.
It's important to note, that I had no such problems with AC prior to infamous "out of abundance of caution" sw update in May of 2019. Back then, I kept my AC at 74 and was fine at all times no matter the outside temp, and the car wasn't even tinted then. As for heater issues, I cannot say.
Anyone has this problem?
 

EVRider-FL

Member
Aug 18, 2015
248
123
South Florida
I live in south FL and don’t have any issues with my AC. I keep it on Auto and set to 72 degrees. No tinting on my windows or roof. 2018 S100D. Don’t use the heater. 😎
 

mymagiccarpet

Member
Apr 11, 2019
176
405
California
Do you have range mode enabled?
no, never use it.
I get that car may prioritize battery over cabin (which says something about overall design or battery), but why blow cold air when it's set to 76 and it's 40 outside...there's gotta be something wrong with it, I don't see connection to battery as this usually happens after driving for some time and battery is at it's operating temperature.
 

mymagiccarpet

Member
Apr 11, 2019
176
405
California
another thing I noticed is that vents on the right (front passenger) blow less air than driver side, and it typically is not as cold when AC is on, and not as warm when heater is on (it can be downright just cold air). I only use single mode climate control.
 

Williamsr

Member
May 4, 2021
6
0
Norway
Has anyone encountered this issue?
All of this happens on auto mode, in single temp operation. All windows are tinted including the roof, and I have the mesh roof cover.
When outside is 75-85F, setting AC to 70 makes me freezing in the car. However, if outside is 90F+ and car has been driven or was sitting outside for some time, setting AC to 70F, does not cool the cabin. Cold air is coming through, but at a very reduced rate - just feels very stingy. On the top of that, at one time when it was 95ish outside, since I couldn't get any cold air, I used manual mode and set it to 11. The car actually reduced the fan on its own to 7 or 8. So essentially, to get proper cooling, you have to either change fan speed or set temp really low, but even that sometimes may not work b/c car will override it.
When using heat, it warms the car fine, but eventually it will start to blow cold air to the point where you are freezing. The only way to get warm air is to increase the HVAC temperature, and you can keep doing that until you hit HI. Interestingly, often the front right vents will blow cold air while the left will blow warm. Eventually, both will blow cold air - not particularly useful when outside is 40F.
SC cannot find anything wrong. They say they run the test, but it seems more like they turn it on once and check. Or don't. This is such consistent behavior that it's impossible to not see/feel.
It's important to note, that I had no such problems with AC prior to infamous "out of abundance of caution" sw update in May of 2019. Back then, I kept my AC at 74 and was fine at all times no matter the outside temp, and the car wasn't even tinted then. As for heater issues, I cannot say.
Anyone has this problem?
2015 Model S 85D sw 2020.48.37.1
My A/C has not worked above 22 degrees celcius temperatures the last 3 years I have owned the car. I drive from Norway to south of Spain every year(3000km each way). And Tesla does not seem to be able to rectify the situation.

The tricky part for me is, in Norway, the temperatures are not that warm, so below 20 deg celcius and not supercharging as often as I do when I drive to Spain it is very hard to notice any inefficiencies until I am mid in the journey with kids in the back seat and the app shows inside temp close to the 40 degree celcius levels, it is very very scary.

The latest A/C service was performed on March 19th 2021. Shortly after that, I had a coincidental discovery the A/C was still not working properly, when I had to drive to the outskirts of Oslo which was a a little over an hour drive(a little over 2 hours drive in total), plus I had not charged the previous night so I needed to supercharge for about 20 min and the outside temperature was between 18 to 19 degrees celcius. The aircondition was blowing warm air the entire trip.

As of writing today it is 5 degrees celcius outside. I have sat in the car in the garage, put the a/c temp at LO activated the ac on the panel to test but to be honest it a bit cold out and really hard to tell the difference if the a/c is working properly because I have not driven car for days and it is pretty chilled inside the car due to low temperatures outside.

Within the last year the car has been in A/C service twice regarding this issue and new service is scheduled for 19th May 2021.
 

nativespinner

Member
May 28, 2018
157
62
Tulsa, OK
Might be an intermittent mixing door motor issue. Mine would not defrost and it turned out the motor was stuck. I removed it, took the motor apart, added lithium grease and it started working again. Then I had no heat in the winter. The thermocouple in the PTC heater would read normal 55 degrees and work for 10 seconds. Next it would read 400+ degrees for 20 seconds and shut off the heater. I replaced the PTC heater and it's been fine since. You may have multiple issues. I used scanmytesla to read my door positions and temperature readings. I think there are three thermocouples on each side of the car in the vents and there is an external one and possibly an internal one. No faults showed on my MCU and I was out of warranty.
 

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