My HS doesn't seem to keep an accurate/consistent interior temp, and I was wondering if others experienced the same or if mine needs adjustment. In other cars I've owned, I set the temp once (~72), and never need to adjust it year round. In the HS, I need to bump it up to around 77 to keep the AC from blasting me with cold air, even when it's only 68 outside (this is miles after I've started home, and the interior is cooled off after sitting in the sun all day). But then the car gets too hot when it's either below 60 or above 80 outside, and I need to bump it down to around 74. Maybe the sun sensor is on the fritz?

Also, I'm used to the AC switching from vent to vent/foot/defrost distribution once the car is at the selected temp, to minimize drafts. And switching to defrost when the wipers come on. In the HS, it stays on vent forever until I manually change the mode (which also switches off auto!). Is this normal? Seems kind of basic for an upscale brand. If this is by design, they really should call it "semi-automatic climate control".

 

Hey Magellan55:

I seem to experience some similar temp issues in mine. Generally, I don't like the AC blowing my eyes dry when I get in and put it in AUTO when it's warm out. I just adjust the temp and select the fan lower. I'll try full AUTO without moving the fan to the lowest and see how it 'blows'. I think you might be right.

dalton
SoCal

 

If the car is in the shade and the temperature outside the car and inside the car is the same, when starting the car with the A/C on I find the cold air blowing to be way too cold - to the point where I'll turn the set temperature way up to 77 or 78 from 72 to settle down the cold air.

When the car sits in the sun, the A/C seems to regulate the temperature better.

 

Funny you mention this. In my '07 ES350, a setting of 72 degrees was comfortable year-round. In my new '10 HS250, a setting of 78-80 degrees is comfortable; 72 is way too cold, usually. On rare occasions, the lower setting seems fine.

Toyota/Lexus car HVAC systems direct most air to the dash vents for cooling (A/C). The floor vents are mainly used for heating. IIRC, a small amount of air is allowed to come from the floor and defroster vents during both heating and cooling modes; the instruction manual should have diagrams/explanations.

If your AC seems weak, make sure you don't have the "ECO" driving mode enabled. That'll dial down the fan and compressor output to save energy.

Related topic: I know starting in '07 the Camry and ES have a new "artificial intelligence" climate control system that supposedly better adjusted temp for comfort. They also have a dual-input design that allows fresh air to be blown out the dash vents while recirculating cabin air out the floor vents -- the idea being to be more efficient while providing fresh air to breath. Does anyone know if the HS has this?

 

Update - I complained about this again to my dealer today (we're just getting to 80 degree days so I was reminded of the problem), and he said it's a common complaint not just on the HS but on the RX as well. Said the Lexus engineers are investigating. Who knows if they will do anything for existing cars but maybe they will fix it on future ones. Hopefully it's just a code change they can flash.

 

Glad you asked since I was wondering the same thing. I have mine set at 72 as well but it still seems to be too cold and I thought it was just me or my car.

I guess i'll try others' suggestion of setting at 77.

 

Just to clarify, I had it set at 73 all winter, and it was fine. It's when the temps get into the 70's and 80's that the car gets too cold - almost like it has an overzealous AC system. I haven't had it happen yet, but I do recall last summer as it got into the 90's, that I found myself dialing it back down to 73 again to keep from sweating. So the problem seems to be in that transition zone between heat and cool. This is particularly annoying when I have to adjust it every day between my morning and afternoon commutes.

As I posted earlier, I've never had to do this in 3 other cars (Saab, VW, Honda) that had ACC. They all adjusted fine by themselves.

 

It's possible that you wore heavier clothes and/or a jacket during the winter, and therefore the lower HVAC temp settings were comfortable, whereas during spring you could be wearing lighter clothes and thus feel colder?

One thing that irks me: When the system is switched from fresh to recirculate mode, the air gets colder, regardless of whether in heat or cool mode. I had this issue with an 07 ES and Camry, too. They need to tweak the system design so the temp doesn't seem to change when transitioning from fresh to recirculate mode.

 

nah, this isn't a clothing issue - never had a problem in over 10 years with other cars. All are garage kept at night and sit out all day in the sun at work. Right now, I'll get in in the morning, it's 55 outside, no jacket, car feels fine set @ 73. End of the day, it's now 75-80 outside, car's been in the sun, after a few minutes the car is too cold and I have to bump it up to 78. You would think the opposite - that the interior is hot baking in the sun all day and I'd want to make it colder.

There was even a day where I had a longer drive mid-morning, and as the outside temp hit about 70, the AC came on and chilled me so I had to bump it up to 78. Same thing when I was driving on a cloudy day and the sun came out. I've got the vents pointed away from me, so it's not a draft issue either.

My guess is either a hyper-active sun sensor, or just some flawed control logic around that heat-AC transition point.