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AC back vents blowing warm air
- Thread starter elplawn
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- ac controls heater hvac
Now that cold weather has returned, I am having the same issue as last winter. I contacted service and text response was the following.
"Hello this is Tesla service. For the Model 3 the front and rear HVAC vents share the same heater starting at the front of the vehicle. In between the center console is a hollow duct joining the two areas. The only way to reduce the rear heat is reduce the overall cabin temperature."
I called and explained to them that I can put my hand on both vents and there is a significant difference in temperature. ie Front is cold and rear is hot. The response was that 'the front is a wide vent and mixing with cooler cabin air and making it feel cooler and that it was not possible for the heater to only be working for the rear". My feeling was that the tech was not going to budge from his position no matter the explanation/example I provided.
In my opinion, is seems to happen on long drives or at least that is when it becomes unbearable/noticeable.
I am going to shoot a video with an infrared thermometer this weekend and email it to them.
Mishakim
Member
I think the problem is they're not answering the right question -- they're saying the HVAC system can't be heating the rear air differently than the front. The problem, it seems, is that heat from somewhere else (i.e, directly from the battery pack under the floor) is heating the rear air. But I don't think Service is going to be able to fix it, unless there's some way to send chilled air to the rear when the pack starts to heat it up, the fix needs to involve insulating the rear duct
I asked that question as well and the response was that the duct is insulated and it was not possible.
It does seem like a likely answer and also aligns with it happening after long trips if heat is coming from elsewhere and building up over driving.
To work around this I usually turn the temperature down to Lo so AC is running full and then the air in the back, gradually cools. I suspect that in the summer there is probably a temperature difference as well but it is less noticeable with cooling vs heating
It does seem like a likely answer and also aligns with it happening after long trips if heat is coming from elsewhere and building up over driving.
To work around this I usually turn the temperature down to Lo so AC is running full and then the air in the back, gradually cools. I suspect that in the summer there is probably a temperature difference as well but it is less noticeable with cooling vs heating
MidwestM3P
Member
Think you're right that it may be related to longer operating times. This happened to us toward the end of a 10 hour highway road trip a couple of weeks ago. It was in the mid-30's outside, we had the inside temp on Manual mode set between 68 and 70 for most of that trip. In the last 2-3 hours of the trip the rear vent would blow steaming hot air and the only way to stop it (other than shutting off the HVAC completely) was to shut the rear vent off from the climate controls. I haven't been able to replicate it completely since then, but did get it to warm up to noticeably higher temps than the climate control was set at after doing in-town driving for 4-5 hours while running errands.
I understand what service is saying in that it's using the same heating unit for the rear vents as the front vents. It makes sense, and that's how most automotive HVAC's are set up. Clearly something else is happening. However, it's not even worth me setting up a mobile tech service appointment as I'd never be able to replicate the issue for him. Frustrating.
MidwestM3P
Member
flashflooder
Member
As far as I know, it is. I still occasionally get it, and all I've seen are reports that Tesla techs are stumped / can't replicate.
Hrm. Happened after a v3 SC stop for me... Maybe they need to fast charge to replicate.
that might be it or longer time with the AC running (we went to a drive thru movie)
I was told by SC just keep the temp below 77 ( i like it @ 79) or turn off rear. Also said future firmware should fix the problem.
flashflooder
Member
The firmware line is their go-to when they're stumped. And FWIW, I almost always have mine below 77 and still get it.
Personally, I haven't been able to figure out the conditions under which it happens. There seems to be no rhyme or reason.
favo
P3D+ owner
Wow, blast from the past! I don't see it in the manual now, but I guess I had some now-forgotten source for that info. Probably someone else on TMC or maybe an Elon tweet. Perhaps someone else can chime in or test it.
Oh I didn't mean to second guess you....I am just trying to get some good info so when I take it in next week I can have some kind of info to be armed with...thanks an sorry if I sounded arrogant.
favo
P3D+ owner
Not at all. I just can't remember what source I had at the time. No offense taken.
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