elba123

Yesterday morning, I noticed outside temperature was displayed on the main gauge as 56 degrees. Internal climate control was set to 71 degrees - auto mode, dual, both sides set to 71 degrees.

After driving about 22 miles in 45 minutes which included a quick stop to drop off a book at the library, I reached a post office. When I came out, I noticed some water had dripped below the car as if the A/C had been running on a hot day.

I can't figure out why water would have dripped after running the heater. I had not used the windshield wiper spray. The car has been inside a garage the whole night - so it was not outside condensation. Is the A/C running even though I have specified a hotter temperature than outside atmosphere? I mean for some reason, is the inlet air being cooled first and then heated? In which case, I better get it fixed while still in warranty period.

I have a 2013 RX350.

Marqevans

Apparently it stays on and dehumidifies the air. You can shut it off through the NAV screen . There are other threads on this issue.

vlad_a

My vent thread, no pun intended:
https://www.clublexus.com/forums/rx-...not-to-ac.html

JT4

Not that big of a deal but a button on the dash would be nice instead of having to go through the menus. I understand that some people keep it set on auto all the time and that's fine..

However, I have no use for the a/c to be on year round in NY.

vlad_a

When the product planning department is located in California or Texas, this is the result we get.
As far as they are concerned, AC is needed year-round.

I recently read an article about the new Miata and how it was made using common sense.
The question was, why not more manufacturers do the same? Because common sense is not that common!

JT4

^^Very true...I tell my wife all the time that it seems like no one has "common sense" anymore... It's sad in a way,,

Cruiter

Siva, there are two 'auto' buttons (at least on my 2010). The 1st is for the system itself and keeping it in auto will not only control the fan speed but also the compressor for temp and humidity. The 2nd one more to the right is for whether it's outside air or recirculated depending on the particulates in the air. Using both of those in full auto mode for me has been great for the interior climate. I will admit sometimes it's like the dog chasing the tail to keep the temp even as well as my Gen I did but it still works well. Also both of them in full auto mode has kept down the humid smells some seem to get.
Now that I've stayed on topic I can stray a bit . I agree on both of these comments. Common sense isn't politically correct anymore . That's why I watch Fox News so I can 'hear' some common sense !!!

JT4

^^I never thought of it that way before...But I agree..

ericsan13

See my step-by-step guide here on the how to use the "Dedicated" A/C Button:

https://www.clublexus.com/forums/rx-...-c-button.html

-Eric

goodrx350

This reply from Marqevens in this thread helped me figure out why sufficiently hot air was not coming even at MAX heat. After switching off A/C from NAV screen, I am getting heated air from the vents.

However, after waiting for someone today for about 30 minutes - outside 53 degrees, inside set to 74 degrees, I saw a big puddle of water flowing from below the RX. DUAL was set to ON. Should I set DUAL also to off? Is A/c somehow running despite switching it off and despite air getting heated properly? I have no desire to waste energy by cooling air first before heating it.

vlad_a

Did you have air blowing at the windshield? That will turn AC on automatically.

goodrx350

To be honest, I don't recall. Thank you for the pointer. I will try without windshield position for the blower.

AL13NV8D3R

I would leave AC on even in winter and even when only needing heat in car. The AC help dehumidify the inside cabin air and will keep the Air Ducts in the cabin mildew smell free. Turning this off with keep your car humid thus increasing the risk you will be one of those people to post on the forum about how to get rid of that sour smell from your AC air ducts.

vlad_a

I believe this to be exact opposite. Turning AC off actually kills mildew. Auto AC is how we ended up with this problem. As soon as I turned AC off when the weather cooled off, any foul smells were gone.
Also, AC will not turn on below freezing. Last thing you'd want is condensed water freezing up.

Cruiter

Not saying you should change what seems to work for you but .....
For all of my Lexus models and for over 60K on my 450h I've used AUTO exclusively even including the auto selection of fresh/recirc year round (you can fine tune that in settings). That being said I've had to 'chase' the temp more on the RX than previous models by raising or lowering the temp but still the air has always been fresh and never once that I can recall humid or moldy odors that prevailed. I let the system control the compressor that I know does shut off when it's really cold. Also I quit using ECO as I've learned to accomplish what it does with my foot and the heat seams to come up faster in the winter.

If you try those settings for a week so to give it an honest trial, I've a feeling you might prefer it. Or not, but I do think Lexus did a pretty fair job on the set up except for the ability to maintain the temps. My RX 300 was much better in that regard.