Hi, I'm new to this site.

just wanted to know whether anyone has any issues with their AC/Heater, it has a mind of its own. I purchased this CPO 2010 RX450h in 2012 and live in the Sacramento region of CA. Here's the issue i've been having since ownership:

1) the heater turns off on its own and vice versa; same thing with the AC.
2) the AC turns on when the outside temp is 55 F when the system was never on.
3) the A/C mode is off during the winter.
4) the heater turns on by itself during spring and summer months.
5) the mode changes on its own as well, for instance I will have the mode set to just have air to the feet, the system will change the mode setting to feet and head mode.

Pretty much my system is acting up and the dealership has updated the firmware but that has made the AC/Heater system act up on an average of twice a week, as opposed to before the firmware update the system would act up once a month to every 3 months.

The service department has given me a loaner 2014 RX450h while they attempt to service my car. Their loaner car did the same thing....the AC came on by itself, their foreman's response to me was that I don't know how to turn off the system!! Gee! I don't think it's hard to know that my system is OFF in my RX when I have to push the fan button until it says "fan off" and in their RX there is an "OFF" button! They had my vehicle for 3 days and found nothing. The next day the system did just so; turn off on its own when I had the system on.

I've read a few threads that people have had with their AC/Heater system and I have not played around with the ECO mode. To me, it makes no sense that the ECO mode should play a part in the system issue. I would consider this something Lexus should look into.

I am now going to video tape this issue so I have proof for them next time. Any feedback would be helpful.

 

Excellent idea and yes, the ECO setting does affect the operation of the climate control system. Make sure you have ECO set off when you make your first video. Then turn it on and make another video. If you compare the two videos, you may see the impact the ECO setting has on the operation of the climate control system. (Basically, it shuts it down to conserve electrical energy.)

 

wow, I did not have that issue, my issue is when I set the air to recycle, it'll reset and bring in fresh air, this happens a lot, I filmed it but now it stopped..

this is an issue because sometimes you drive by a semi and it's blowing exhaust, I was like why am I smelling this crap, I look down, its on fresh air mode

 

I have one of the very 1st 2010's made. I may be reading your attempts wrong but what I'm understanding is you're trying to manually turn things on or off. The system is supposed to be put in 'AUTO' year round then you adjust the left & right temps as you like them. At times in the winter the compressor will still operate to control humidity but it will do it in conjunction with the heat. If it gets bitterly cold like in the 20's or lower then the compressor won't operate. Try full auto and just adjust the temps. I think your problems will be over.

BTW, welcome to the site and let us know how it works. Seems the new one worked the same way so .....

 

Thanks for all the feedbacks and comments.

The advisor was the one that had turned off the AC mode for me and explained about the compressor.

I did video tape how I have the system set, 2 days in a row I was able to document the issue. It's really frustrating bcz everyone's comments are exactly what the advisers has told me. The foreman does recognize that I do have an issue but he was unable to replicate the issue.

I will update more when I video tape the AC/heater setting with the ECO mode on off. as well as, when I bring back the car to the foreman to show him the videos.

 

Resistance if futile. The climate control has a brain of its own and little of it can be manipulated.
Here's my thread on AC:
https://www.clublexus.com/forums/rx-...not-to-ac.html

There is a custom setting to disable auto-AC. It does little, but it is there. Make sure dual climate control is off.

Ricirc mode also has a mind of its own. Unlike AC, it is cearly visible (at least until the next Nav release) and somewhat logical.. When the temps are high, the recirc will turn on, along with AC. If the front defrost is on, it will switch to fresh air.

 

Until they find a fix for your Auto A/C mind of its own, just use manual operation.
1.Leave the setup, vehicle customization, climate settings, AUTO A/C settings in the ON position. 2. Set dual temps settings preference. 3. Press the AUTO button on the dash to OFF (no green light). Everything then becomes manual according to your selections.

Will be interested in your updates, and also eventual solution to the auto A/C problem. Welcome to CL.

 

Vlad_a,
thank you for the thread, it was very helpful. I feel that I have a good grasp on the compressor trying to compensate for the cabin temp but I feel my issue extends way beyond that.

For instance, a few days ago the outside temp was 61 F, heater off, AC button off, fresh air button selected. I ran my errand and got back in the car and the heater was on. Also, the mode setting and the recirc button will change in the middle of a drive!?!?! Frustrating!

go3Ds,
I have the set up to how you mentioned it except for the AC mode is off (per the dealership).

Cruiter,
When you say 'AUTO' what button are you referring to? The AC button on the Nav screen or the 'AUTO' button on the dash board? Bcz I have both buttons off. I don't use the AUTO button on the dash board bcz the fan stays on max high and doesn't come back down.

I hope I don't drive myself or anyone else insane since there has already been a similar thread https://www.clublexus.com/forums/rx-...not-to-ac.html

 

Cruiter means the "Auto" button that's on the dashboard. I use the "Auto" mode 99.5% of the time as it serves its purpose just fine for me. As for the Fan staying on max and doesn't come back down, that's odd. In the heat of summer, the fan will run pretty high for a minute or 2 but always goes back down. Just adjust the temp controls up or down to your liking and the fan should compensate.

 

After trying everyone's advice here on this forum I finally finished documenting and videotaping my Climate issue. The forman has turned off the AC system to OFF, as well as, the ventilation to OFF both from the vehicle's dashboard and from the dealership's computer system that controls the vehicle's software.

He was confident that turning everything OFF on his end and the vehicle's end that I wouldn't (shouldn't) have anymore issue of the Climate system turning OFF and ON on its own.

I couldn't be too upset with them since they didn't charge me for my oil change (even though I knew the issue at hand wasn't going to be resolved, I just wanted to believe it was).

Hahaha! The foreman's solution did not fix the problem!! The belief only lasted 2 days without the Climate system acting on its own. So, now I will have a second update when they fix my Climate issue again.

 

One of the issues could be the internal sensor. If you look below the steering column, on the right side, you will see a little slotted opening. Usually, there is a heat sensor and a vent pipe connecting to it. A common problem for the IS300 was people removing the bottom panel and not reattaching that vent pipe back in. It could be the same on the RX.