Unwanted seat heating
06-16-17, 05:43 AM
#31
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So I tried this out again today, once when I just got out to the car after it had been sitting in a parking lot all afternoon in roughly 90 degree ambient temperature, and again after driving home and parking in the garage for a half hour. On the way home from work, the seat got WARMER in the lower part of the seatback, though cool air was coming through on the bottom cushion. Mind, this was after I drove for about 2 minutes, which gave the air conditioner a chance to really start cooling. Later, when leaving my garage, when the car was considerably cooler, it seemed that the issue had disappeared, even with the fans on max speed. I left them on for a couple minutes and didn't really notice anything, so I turned it off. So, I am wondering if it has something to do with the temperature of the air in the car at the time the ventilation is turned on. Also, the warmth I felt from the seat back went away pretty quickly after I turned the fans off, and it was less intense when on low speed. This all seems to support that it's literally blowing hot air at me when the air inside the car is really hot.
06-16-17, 06:00 AM
#32
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I agree... but unfortunately that's when you want it and need it most. Hopefully we can find a solution for it... whether it is a new fan/motor or some sort of modification to the system. If 2017s really don't have the problem maybe there is a new part number we can retrofit to ours.
06-16-17, 07:54 AM
#33
drives cars
I am in line with the concept that the temp in the car seems to affect the seat cooling system. Mind you I have only owned the car for 6 days but mine only seems fail when I want it most, when the car has sat in the heat for a while such as a day at work. I took some video and will try to clean up to link here this weekend.
06-16-17, 08:13 AM
#34
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Naturally, this defeats the purpose for which you'd normally want to use the ventilation. I tried it again on the way to work this morning, and it felt nice and cool, no heat coming from the lower seat back. Sadly, it seems all the seat ventilation does is ventilate, true to its name. That is, it just recycles air that's already in the car.
06-16-17, 08:35 AM
#35
drives cars
At first I thought that, but it seems like there is more to it than that. When I stuck my hand under the seat, where it is presumably pulling air from, the air is *much* cooler than the seat surface or the air that comes out of the seat. Also, when I put my hand on the seat surface and it is on, it gets hot. Then I turn it off, and it gets cool. Turn it back on and it gets hot again. Something in the loop is *adding* heat, it's not just warm ambient air causing it, although it seems to be worse when the ambient air is warm.
06-17-17, 06:59 AM
#36
just a few thoughts.
I have experienced this effect. It is not a malfunction in the system.
Remember, this is just a ventilation system, not a cooling system. It may not feel cold, but at least it helps keep it dry. Like others have said, the system is just circulating the air inside the car. Also, if your car was hot when you got in it, remember that all that piping that the air is traveling through is hot, as well as the leather on the seat. It may take some time, even after the air temp in your car has dropped, for it to not feel hot.
Another thought. I'm not aur exactly where the intake for the seat fan is... I'm assuming underneath. If so, it may help to set your a.c. on the foot setting to get everything cooled down faster.
I have experienced this effect. It is not a malfunction in the system.
Remember, this is just a ventilation system, not a cooling system. It may not feel cold, but at least it helps keep it dry. Like others have said, the system is just circulating the air inside the car. Also, if your car was hot when you got in it, remember that all that piping that the air is traveling through is hot, as well as the leather on the seat. It may take some time, even after the air temp in your car has dropped, for it to not feel hot.
Another thought. I'm not aur exactly where the intake for the seat fan is... I'm assuming underneath. If so, it may help to set your a.c. on the foot setting to get everything cooled down faster.
07-23-17, 03:40 PM
#37
This is BS
So this problem never got fixed? I am going in to the dealership at my next oil change and going to ask them to fix this problem. My car is still covered under the 4 year warranty so I am going to demand they swap out the fan for one that doesn't roast your back when driving. How are you guys just going to let it slide and say I am just never going to use the feature? If there is a problem, they NEED to fix it. Maybe they can switch the fan from one of the other models or something. If they don't play ball they need to refund money or something!!
07-23-17, 04:19 PM
#38
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So this problem never got fixed? I am going in to the dealership at my next oil change and going to ask them to fix this problem. My car is still covered under the 4 year warranty so I am going to demand they swap out the fan for one that doesn't roast your back when driving. How are you guys just going to let it slide and say I am just never going to use the feature? If there is a problem, they NEED to fix it. Maybe they can switch the fan from one of the other models or something. If they don't play ball they need to refund money or something!!
I did bring it to Lexus. They said they could not understand how this was possible but I gave them a video which showed it clearly (I will try to post today). They did not argue but said the only thing they could come up with was that when the car sits all day baking in the sun, possibly rails in the seats get hot and the ventilated seats pull the hot air across to these locations. I wasn't buying it and he didn't argue but they didn't know what they could do. I was tempted to pull the seats a part but started to lose motivation on that. For me, it only happens when the car sits in the heat for hours (albeit the primary time I want the seats to ventilate). That's where I'm at so far. Wish I had better news.
07-23-17, 06:08 PM
#39
Pit Crew
I'm still having this problem too. I particularly don't understand it since it happens also to the passenger seat when no one is sitting in it. I'd sort of get it if all of the stored hot air gets pushed to the top of the seat and gets blocked in since your leaning back in the seat. But this clearly isn't the case.
08-03-17, 11:16 PM
#43
Driver School Candidate
Up until now I've also been confused and frustrated why sometimes the seat back feels hot and sometimes it feels cool. After reading many posts, I decided to inspect under the seat and open up (unzip) the back of the seat and see how the ventilation works.
First, as far as I can tell the ventilation is just fans pushing air. No AC coolant plumbing. No thermoelectric (peltier) cooling.
Second, there are 2 fans with separate independent air flows. There's one on the seat bottom, pan, which sucks in air directly from below the seat and blows up into a square flat bladder glued to the seat cover. Air then flows out up through the preforated holes but only over the bladder area with most of it flowing between your thighs. This air travels a very short distance from below the seat to the top of the seat and it only touches the air bladder and seat cover. So the outlet air temperature is about the same as the inlet air below the seat. Even if the seat cover is hot, it will cool down quickly as there isn't much material there to hold the heat. On a hot day, the air in the shade below the seat is always cooler than the air above in the sunny cabin. So this air below the seat feels cooler than the upper cabin air. This is also why some say directing AC air to the floor vent helps a little. However, the floor vent doesn't blow directly into the seat bottom fan intake. Some posts talk of adding metal or cardboard deflectors behind the seat to help direct or trap the AC floor vent air toward the fan. I think this is a good idea.
The second fan is located high up in the seat back about 4 inches from the top, not including headrest. I think it's the fan's location and how the air flows which is responsible for the air coming out being hotter or cooler. I unzipped the back seat cover and looked around with a mirror. This fan also blows into a square bladder glued to middle of the seat back. Again the air comes out mostly where the fan attaches to the bladder which is right in the center with some flowing out slightly to the left and right of center. The bladder glue pattern limits the air flow to just those regions. Unlike the bottom fan which draws in air from below the seat, this fan draws in air from the interior of the seat back. The sometimes hot or sometimes cool seat back. On a hot day, the inside of the seat back is full of very hot air and the seat back itself is also hot. The ventilated seat back will initially be blowing this very hot air on to you. Once the air starts flowing, where does seat back get its air from? My best guess so far is that air is drawn in from two areas. One is from those preforated seat cover holes around the top of the seat back. Plastic sheets lines the inside of the seat back except near the top and very bottom. Unfortunately, on a hot day the air near the top of the cabin is still pretty hot so hot air going into the seat back, hot air coming out on to your back. Plus the seat material is still very hot so it makes the air even hotter. The other seat back air inlet is near the bottom but it's a small opening. This probably cooler air then travels all the way up the hot seat back to reach the fan at the top. So again more hot air. Things only cool down when the air in the entire cabin gets cool enough which is too late for many of us.
On a cool day or early morning when the car is cooler than the outside air, the opposite situation happens. The seat vent air feels cooler.
So that's my theory to this puzzle.
So are we stuck with this forever, I think not. I"m experimenting with directing cool AC air from the floor vent directly to the upper fan area. I used cardboard tubes, lots of tape and plastic bags. It seems to cool better on a hot day. I'll have to replace the card board tubes with a flexible hose (vacuum cleaner hose) so the seat can move back and forth without things coming undone. A fun experiment but hopefully cool. At the very least, I would suggest sealing the area under the seat (front, back, sides with cardboard or something) so the bottom fan and eventually the top fan can draw in cool air from the floor vent.
Stay cool or at least ventilated...
First, as far as I can tell the ventilation is just fans pushing air. No AC coolant plumbing. No thermoelectric (peltier) cooling.
Second, there are 2 fans with separate independent air flows. There's one on the seat bottom, pan, which sucks in air directly from below the seat and blows up into a square flat bladder glued to the seat cover. Air then flows out up through the preforated holes but only over the bladder area with most of it flowing between your thighs. This air travels a very short distance from below the seat to the top of the seat and it only touches the air bladder and seat cover. So the outlet air temperature is about the same as the inlet air below the seat. Even if the seat cover is hot, it will cool down quickly as there isn't much material there to hold the heat. On a hot day, the air in the shade below the seat is always cooler than the air above in the sunny cabin. So this air below the seat feels cooler than the upper cabin air. This is also why some say directing AC air to the floor vent helps a little. However, the floor vent doesn't blow directly into the seat bottom fan intake. Some posts talk of adding metal or cardboard deflectors behind the seat to help direct or trap the AC floor vent air toward the fan. I think this is a good idea.
The second fan is located high up in the seat back about 4 inches from the top, not including headrest. I think it's the fan's location and how the air flows which is responsible for the air coming out being hotter or cooler. I unzipped the back seat cover and looked around with a mirror. This fan also blows into a square bladder glued to middle of the seat back. Again the air comes out mostly where the fan attaches to the bladder which is right in the center with some flowing out slightly to the left and right of center. The bladder glue pattern limits the air flow to just those regions. Unlike the bottom fan which draws in air from below the seat, this fan draws in air from the interior of the seat back. The sometimes hot or sometimes cool seat back. On a hot day, the inside of the seat back is full of very hot air and the seat back itself is also hot. The ventilated seat back will initially be blowing this very hot air on to you. Once the air starts flowing, where does seat back get its air from? My best guess so far is that air is drawn in from two areas. One is from those preforated seat cover holes around the top of the seat back. Plastic sheets lines the inside of the seat back except near the top and very bottom. Unfortunately, on a hot day the air near the top of the cabin is still pretty hot so hot air going into the seat back, hot air coming out on to your back. Plus the seat material is still very hot so it makes the air even hotter. The other seat back air inlet is near the bottom but it's a small opening. This probably cooler air then travels all the way up the hot seat back to reach the fan at the top. So again more hot air. Things only cool down when the air in the entire cabin gets cool enough which is too late for many of us.
On a cool day or early morning when the car is cooler than the outside air, the opposite situation happens. The seat vent air feels cooler.
So that's my theory to this puzzle.
So are we stuck with this forever, I think not. I"m experimenting with directing cool AC air from the floor vent directly to the upper fan area. I used cardboard tubes, lots of tape and plastic bags. It seems to cool better on a hot day. I'll have to replace the card board tubes with a flexible hose (vacuum cleaner hose) so the seat can move back and forth without things coming undone. A fun experiment but hopefully cool. At the very least, I would suggest sealing the area under the seat (front, back, sides with cardboard or something) so the bottom fan and eventually the top fan can draw in cool air from the floor vent.
Stay cool or at least ventilated...
08-05-17, 04:09 AM
#44
I've only had my 2015 IS250 a week. But on mine the seat cooling is different depending on the location it was parked. It's crazy hot where I'm at. But when I've been parked under a shade. You can feel the cooling air kick in the drivers seat. Parked in the sun and it seems like it doesn't work.
07-20-18, 02:21 PM
#45
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Seat heat
I have a 2017 Is200t and it seems that the seat backs get hot when the seat cooling is turned on. Nothing like a sweaty back on leather seats in Florida. You would think that they could solve this problem as it appears to have been a problem for several years.