2011 RX350 Cooled Seats Don't Cool

[Steve1952]

My 2011 RX350 has heated and cooled seats. The heat works, but they won't cool. I can hear the blower motors on both seats, but no (or almost no) air comes through. I also have a 2007 GS350, and they work fine, so I know how it's supposed to work.

My theory is that the cooling vents are clogged or they've become unattached to the AC unit. Has anyone experienced this, and if so, how do you fix it? Thanks,

Steve

[pj8708]

Hi Steve and welcome. Over the years I have had five Lexus ES & RX 350. All of them have had heated and cooled seats. The heated feature works well but the cooled seats have never worked. A lot of us have tossed this problem around and some say theirs works, others, no. The heat feature works using a heating element. The cooling feature use's just blowing air through the seat cushions.

 

I have taken my cars in on numerous occasions, but there is no fix. I would suggest doing a search of our database for more information and opinions.

Let us know how things turn out.

Paul

[Steve1952]

Thanks Paul, I hope to find a solution. 

[Les Lex 2018]

Same question in a new 2018. My guess is that if the driver is sitting on the seat, the air will be blocked.

So the design is therefore to cool the leather seat, which in turn will then cool the driver indirectly.

I will leave the RX in park with the air on and place a strip of paper on the seat to see if it moves around.

[pj8708]

Hi Les,

The seat cooling feature is always a head scratcher. On a couple of previous ES 350's I told the service writer at my dealer that my cool feature did not work. At this same time I had a Volvo 2007 S80 with the cooling feature as well. It got so cold you had to almost dial it off.

Each time I went in to the dealer they said that they could not find anything wrong. Finally, I stumbled upon the solution. If you turn the temperature way down, say 65', and the fan on high with the cool setting. The seat will cool down quickly. Adjust the temperature to the desired setting.

Paul

[Les Lex 2018]

Thank you Paul!  I’ll investigate your findings today and report back hopefully with similar results.

So far, I’ve not seen any indication that the feature is working but the weather has been cool and I don’t leave the car out for long periods like you would if you used it for work so have yet to drive it on a hot day sitting in the sun. The RX only has 300 miles and I’m still testing all the features.  Thanks for the added info. Did not understand after reading the book that the seat fan could be tied into the speed of the AC Fan. 

[Les Lex 2018]

Ventilated seats are a big let down.  I went to setting/vehicle/ventilated seats and set the 0 (normal) to max cool (-2).

set mode to S_Mode.  Cranked down the AC and turned on the cooling to all high position (3-green LEDs.

No air coming form the seats and the seat is warm except for the front 5 inches of the seat.

Took it to the dealer and they verified that all setting were correct and that it was working because the front 5-inches of the seat was cool which the rest was ambient temp.  Used a powerful LED flashlight to see if any light shines thru the seat anywhere and nothing so I don’t believe its designed to be “ventilated” BUT rather cold air blown under the seat where something is better than nothing.

A true head scratcher in deed, Paul.

[Gamalot]

This may be related to the issue I am going through right now with mice getting inside the air ducts and building nests on top of my cabin air filter. How they can get from the ground and up in the air ducts and then inside the car only to drop out from underneath the dash is a mystery. Believe me, if they can build a nest on the top of the cabin filter then they can build nests in all the ducts and block the passageway. I have spent the past three days trying to get the mice out and in the process I have found dead baby mice in the ducts and on the passenger side floor mat. Since the temps are going up the entire inside of the car stinks of dead mouse and I have no idea where the culprits might be. Just imagine if you can having your wife driving along in her luxury Lexus and mice falling on her feet at 65 MPH.

[Les Lex 2018]

Aren’t those air vent intakes located in front of the windshield and already grated to prevent rodent/bird intrusion?

Could be coming in from the inside and not via the vents. But not likely you or anyone would leave a Lexus outside with the windows or sunroof open long enough for a bird to build a nest and hatch a chick.  So neither your scenario or mine makes much sence.  Sorry, but no help.

[Gamalot]

I have no idea where the air vent intake is located but can tell you for sure the mice get in my garage and then find their way into the car from the top side of the cabin air filter box which is located on the passenger side behind the glove compartment. First we found new born blind mice on the passenger side floor mat and when I investigated and removed the cabin air filter the entire area above the filter was loaded with a mouse nest and 2 more dead baby mice. I set traps in the garage all the time and catch the mice and suspect I likely killed the parents after they had the babies up inside of the vents. I have set traps in the car cabin on the floor mat but have never caught a mouse in the car cabin which leads me to believe the full grown mice can get in the ducts from outside but only as far as the top side of the cabin air filter and only the tiny baby mice can get inside the car cabin. My thought is if they can stuff the ducts above the cabin air filter full of nesting material it may be possible they could stuff the ducts for the seat cooling so no cool air or very little can go to the seat. Directly below the cabin filter is the squirrel cage fan that pulls the outside heated or cooled air in and blows it through the car.

 

Gary

[Les Lex 2018]

You may have finished off the mice yourself if and when you left the car out somewhere on a hot day.

Nothing or no one survives that.  Call pest control - they are brilliant when it come to ways of eliminating rodents.

Too quote my pest guy, “the only thing that attracts rodents is food, a warm place to stay, and privacy”.  In other words, they are hungry, warm blooded animals that enjoy your crumbs, but don’t enjoy your  company. Sound like they found one or two of those needs in your Lexus.

As for vented seats, there is no air blowing thru the seat and the car is new. I’ll ask Lexus Support to define “The meaning of “vented” so I can troubleshoot it myself. The dealer consultant was no help by saying that it really doesn’t “vent” like you would think.

Good luck with the pest control guy - you need one...

[Gamalot]

Les, My response here is more for the OP 2011 RX owner who is getting no air flow through the seat ducts. Our 2015 RX is never left open either in or out of the garage. The mice do in fact come in through the vent ducts and this is the only way they could possibly get to the top side of the cabin air filter box. Once there I do believe they could build nests in any or all of the ducting throughout the entire car which would and could impede the air flow.

Hiring a pest control company to rid my country home of field mice would be an effort in futility but certainly would make the company a major profit for their endless efforts. Mice are a way of life out here and they get in no matter what we do but they should not get into the ducts of our Lexus. A schematic of the actual duct work in my RX sure would help to guide me on where the intake is so I could fashion a screen or barrier of some sort to keep them out. Mice do build nests in my tractor, boat, shed, garage and just about anywhere else including on top of the engines. As fast as I can catch them the next generation is ready to invade. Very destructive critters BTW and capable of doing a lot of damage as they chew their way through wiring and materials while building their nests. Remember I did say they are not inside the cabin of the car but they are in the ducts and apparently only the tiny babies can wiggle their way through an opening and end up inside on the floor mat, no adult mice have ever gotten inside to the best of my knowledge and only into the upper cavity of the air box above the cabin air filter. We do agree on one thing. There should be no way for mice to get to where they are building their nests and that is a Lexus defect IMO. The stench of dead mice should not be blowing throughout the cabin of a very nice luxury vehicle the minute the fan turns on. 

[Les Lex 2018]

I checked the ducts on the 18 RX and I think you are absolutely right.  The vent openings are 3/16” x 7/16” slots.

This IS BIG enough to allow some rodents in.  OK, then here is the fix.  Go to Loews and have them run you off about 3 or 4 feet of their aluminum screen off the roll they use for this purpose. Open the hood. Just under the windshield wipers is a recessed bay that has 4 banks of grated opening (on the 2018 anyway).  Cut out the screen to fit over each air bank.  Then use silicone caulk around the rim to hold them over each of the banks.  Let it dry.  Cons: That may restrict some air flow but ask Lexus about that.

Also, do mice like to chew on aluminum screen?  When I had mice in the attic, they had me stuff scree into the air vent between bricks on the outside and that did keep them out.  

Really hope this helps.

[Gamalot]

Thanks Les. I suspect there is an intake opening under the front wheel wells toward the front. I have not had the time yet to take off all the plastic covers in and around the engine compartment so it is very hard to assess where they might get in from. I had hopes there might be a Lexus Tech viewing some of these threads who might have first hand experience with all the covers off. I do have my own thread going on this subject and only posted here to give the OP some possibilities of what might be his issue. So far with our 2015 RX 350 the cooling for the seats works fine and once I get the dead mouse stink out I should be fine for the summer. Mice tend to seek shelter in the garage and cars only during the cold months.

 

[Les Lex 2018]

The inside air intake is ALWAYS below the windshield because that is the point where the air hits the windshield creating a high pressure point, needed to force air inside.  The somewhat polluted air that gets sucked into the engine compartment due to blowby and the like is channeled down and under the car.  The small vents found elsewhere are used to prevent a pressure impulse when a door is closed.  Those should have some sort of grating also to prevent insect and amimal intrusions.  Only see them in the rear door well.

Just what I was always taught.  IF you have an animal stuck in your ducts, it’s most likely Jamed up against the heat /air exchanger and I think getting to that may me hard.  But I am not a mechanic.

 

[Gamalot]

I was a mechanic during Vietnam working on H-47 Helicopters but in this instance I am hoping to find the Easy Button so I need not tear the entire shroud under the hood apart to find where the critters gain access. Short of a Toyota/Lexus Tech chiming in here I could also just take it in to Lexus where I bought it and the 7 year extended platinum warranty and pitch a super BE-ich and force them to fix their defect.

 

Gam

[Les Lex 2018]

Now you’re talking. Call Lexus!  By the way, my 350 has the exhaust vents next to the rear hatch and the grating on them would surely keep the mammals out.  Let us know what they find.

Well guess what?  Had to call Lexus today and give them the bad news.  I put an outdoor thermometer on the seat this AM. I taped it down and ran the wire and the thermometer into the console.  I sat on it in the 350 until it stabilizes at 91 degrees.  Then I made a trip to Cabellas with the AC set to 66 degrees.  The temp element was exactly in the middle of the seat. Absolutly no change in temp. Not even a tenth of a degree.

 Now all I do have to do is take it in to Lexus and show them the thermometer and ask them what happened to the ventilated seats? I love it!

Les, SP-5, MACV 67 - 69

[Gamalot]

Thanks again Les. My nephew runs a big auto body shop in NJ and is well acquainted with this rodent issue. Not just a Lexus thing but with many makes and models and they find the critters all the time during the cold months. He is sending me the push pins needed after I yank all the plastic covers over this weekend, weather permitting. He also agrees with you that under the windshield where the wiper motors are is where the air comes in and the most likely place the critters gain access. At his shop they have seen cars burnt to a crisp and totally destroyed as a result of mice and other critters gnawing on the wire harnesses. He will send me a couple pictures of fried mice later today.

Sorry I have no input regarding your seats not cooling as they should. Ours in the RX and the ones in my 2016 4Runner limited cool very nice on hot summer days. I can hold my hand on the seat bottoms and backs and feel cool air flowing.

Gam

Helsupron-6 NAS Norfolk

[Les Lex 2018]

Thanks for the info on the Toyota.  My RX goes in tomorrow morning for my only problem, and We’ll have the answer on cooling for sure.

Dumbest thing I did in last ten years: Putting up a bird feeder - roof rats, mice and chipmunk envasion.

Never again...

Les, MACV 67 - 69

[Les Lex 2018]

Had the experts study my RX-350. Finally solved the mysteries behind ventilated seats. So here is the story.

Only the front 8” section of the seat is ventilated. So the rest of the 12” from the front section to the backrest get no ventilation and no cooling at all, per my test using a temp sensor placed on the middle of the seat.

Because the 2016 to 2018 RX-350 seats are ventilated (and only partially) and not hooked up to the AC ducts, they can only cool by passing a slight amount of ambient cabin air thru the front of the seat. Even if you put tracing paper on the seat, the paper does not move. Air flow is only noticible to some people. Lexus service say my RX is therefore working fine.

So, Paul is right in a sense.  The fan gets it air from the floor, so what ever temp that is, that is the air that will cool the bottom of the front 8” of your seat.  Since AC cools best in hot weather coming from the top vents, it would be a trade off to select air from the top and the bottom, just to get more air under the seat to indirectly cool the seat.  But you’d want to do that to make seat cooling work to maximum benifit. 

My last and final test will be to measure the temp under one of my legs where cooling is actually occurring. I’ll measure the temp w/o the Air on and then note the reading after using max air for the next 10 minutes.  Since there is no advertised cooling improvement, there can be no pass/fail criteria. In other words, it is what it is.  But inquiring minds wanna know.

[Gamalot]

Thanks Les, great info. I have to do some testing this weekend when the wife's car is here during the heat of the day. I do know this for sure in my 4 Runner limited with leather seats. When I have the seat cooling in max mode it works great and throughout the entire seat bottom and back. If while sitting in my seat I lean forward away from the seat back I can both feel and hear the air blowing through the back upright. After a day on the golf course and in shorts and a light shirt my seat gets noticeably cold on the ride home but I don't get to drive the Lex much as it is the wife's daily driver.

Gam

[Les Lex 2018]

Interesting abut the 4-Runner, a more expensive ground craft.  The system in the latest RX is a different animal.  They punted on that option.

Lexus of Huntsville agrees with me that neither Toyota or Lexus wants to discuss with anyone in detail, the exact equipment and functional nature of their equipment. As a result, there is a lot of information and disinformation on sites like this because each model is different and you have to pry info out of their folks to get any useful information, as evidenced by my encounter with ventilated seats.

I would be generous at this point, if I gave that option two stars. But it sounded great in the brochure.

BUT after a month of very extensive testing, I can tell you that this RX=350 is 100 percent operational per the OM.

[Gamalot]

I want to investigate to see if the system in our 2015 RX 350 is possibly different from in your 2018. I don't know if you have the leather seat option like ours but the leather has hundreds of tiny perforations for the venting to come through. Not sure how they could do that on cloth seats.

I find these forums to be very informative for the most part. Sure there are the few who don't know what they think they know but need to sound smart. How the critters get in is my focus and once I get that figured out I will report my real findings here. Comparing my 4 runner to the RX is  apples to oranges. The RX is certainly the luxury between the two and a pleasure to drive and take long trip in. The 4 runner is bigger and more capable for my manly needs of towing the boats and trailers with just enough luxury to make it a great and very comfortable ride. Two completely different animals but both are nice vehicles. My wife had 3 Toyota Rav 4s which got the job done through some nasty winters here in the NY Catskills but she absolutely loves her RX. I had a Tacoma before the 4 runner and in all reality I prefer the pick up for my needs but can live with the SUV 4 runner for a while. 

[Les Lex 2018]

Thanks for the investigation:  Here is an update:  Yes on Leather seats. IF you take a vacuum cleaner and place the water vac attachment on the center of the seat were I monitored zero cooling, it is sucking into a dead zone.  There IS NO venting there. Not the same for the front part.

So Lexus was right in saying that it IS WORKING.  Just not like some (like myself) would expect it to work.  So as promised, I placed the sensor under my leg yesterday.  The zero cooling test case would have been 93 degrees.  The front part under my leg actually got to 88. The cabin temp was 80. So YES, it is passing  by 5 whole degrees. Ain’t exactly going to give anyone a frost bite.

I traded the RAV4 for this RX.  Can’t see a 4-banger in what is essentially a truck.  There is something BAD wrong with a truck horn that goes beep beep instead of HONK HONK.  Enter the RX.

I will never own anything but an RX-350 after test driving it.  The RAV4 is in the lower compact class. The RX is in the mid-size class.

The RAV4 is not in a luxury class.  The RX compares “closest” with a loaded up Highlander, size, power wise.  I test drove the Highlander.  Not quite the same.

My favorite mountain car, believe it or not, was the Camry XLE with Michelin tires. I took it to the Rocky Mountain Nat Park above Bolder, Co to do the Warrantee test on it.  IT passed.  The Braking position B on the Hybrid was awesome coming down off of the 12,400 foot top.

The only thing that hurt my feelings when I got the RX were warm seats and junkie Bridgestone tires.  How low can you go.

[Gamalot]

You have about the same assessment as we do regarding the Rav4 and the RX350. Living here in the NY Catskill mountains, Snow Country, it was essential that my wife had a vehicle capable of severe winter driving because her work required her to be there no matter what. Snow country is also road salt country and the salt turns any vehicle into a bucket of rust in short order. With this in mind we leased 3 Rav 4s for her and turned them in at the lease end for a new one. Her last Rav was the LXE model and a bit nicer overall. The Rav 4s are just a basic vehicle but with good reputations and we never once had to have anything repaired on any of them. A promotion at work equated into an upgrade of her vehicle so I picked the 2015 RX 350 and she loves it. Yes to the junk tires standard equipment but I bought a complete second set of stock rims and outfitted them with Bridgestone Blizzak tires for winter treads and have never looked back. Great tires and turns the RX into a tank on snow and ice covered roads. My one and only complaint is with these damn TPMS  (Tire Pressure Monitoring Systems) every spring and every fall I have to get the wheels reprogrammed at a dealer or the tire place when I swap. One would think the system could be smart enough to have two sets of programmed TPMS sensors stored but it is just a PITA. I would buy the programmer myself except they are ridiculously high priced and subject to change as technology becomes obsolete. The Rav 4 rides jittery and is a sort of tin can while the RX rides very smooth and quiet. We test drove a new Highlander and she did not like it at all and we also tested a Subaru Forester that failed in every aspect.

I know for sure the heated seats in the RX work great and once we get some hot weather here I will be testing the cooling function. We still had snow on April 30th so it will be a while before the AC is actively employed. Mice building nests in the vents and then finding a way inside the car is perplexing but I will correct this issue hopefully this weekend. I give Lexus a big thumbs down on this issue for sure. In 9 years with Rav 4s in the same mouse infested garage we never had this issue with them which leads me to believe there is a direct opening somewhere that should not be.

Gam