AC / AUTO Settings
Thread Starter
Intermediate
Joined: Aug 2024
Posts: 261
Likes: 138
From: MA
AC / AUTO Settings
I would like to know what is the best practice.
I leave mine set to "AUTO" , I do not set/press "AC". I just turn temp **** to desired temperature and it kicks on AC or Heat as needed.
On my previous vehicles I would press "AC" to On when needed - but then shut off the "AC" before shutting off the engine.
I always thought I was saving additional load on the engine while starting with the AC compressor off and maybe saving excessive compressor wear also.
Will I cause more wear & tear by just using "AUTO" ?
I leave mine set to "AUTO" , I do not set/press "AC". I just turn temp **** to desired temperature and it kicks on AC or Heat as needed.
On my previous vehicles I would press "AC" to On when needed - but then shut off the "AC" before shutting off the engine.
I always thought I was saving additional load on the engine while starting with the AC compressor off and maybe saving excessive compressor wear also.
Will I cause more wear & tear by just using "AUTO" ?
2nd gear
Joined: Jun 2025
Posts: 2
Likes: 6
From: IL
ChatGPT said:
Using "AUTO" does not cause more wear and tear. In fact, manually overriding the system unnecessarily could reduce efficiency and comfort.
✅ "AUTO" Mode in the 2025 NX 350: Best Practice
The climate control system in your Lexus is fully automatic and intelligently manages the AC compressor, fan speed, airflow direction, and heating to maintain your desired cabin temperature with maximum efficiency. When you:- Leave it in "AUTO"
- Set your preferred temperature
- Don't manually press the "AC" button
🔧 Why You Don’t Need to Manually Turn Off the AC Anymore
In older vehicles:- The AC compressor was belt-driven and engaged by the engine.
- Turning it off before shutting the car off reduced engine startup load.
- It may have helped avoid wear on older mechanical compressors.
- The AC compressor is an electronically controlled, variable-speed unit.
- It only runs when needed and ramps up/down gradually.
- There's no mechanical clutch "shock" like older systems had.
- The engine control unit (ECU) ensures no excessive load at startup, regardless of AC state.
❄️ What Happens When You Use "AUTO"
- If the outside air is warm and you set the temp to 70°F, the system will activate the AC compressor, even if the "AC" button light is off.
- If you set it to 80°F on a cold day, it will engage the heater only.
- In both cases, Lexus’s logic protects the system components from unnecessary use.
🧰 Final Answer: Will AUTO cause more wear and tear?
No.Using "AUTO" does not cause more wear and tear. In fact, manually overriding the system unnecessarily could reduce efficiency and comfort.
Pole Position
Joined: Aug 2011
Posts: 2,035
Likes: 857
I would like to know what is the best practice.
I leave mine set to "AUTO" , I do not set/press "AC". I just turn temp **** to desired temperature and it kicks on AC or Heat as needed.
On my previous vehicles I would press "AC" to On when needed - but then shut off the "AC" before shutting off the engine.
I always thought I was saving additional load on the engine while starting with the AC compressor off and maybe saving excessive compressor wear also.
Will I cause more wear & tear by just using "AUTO" ?
I leave mine set to "AUTO" , I do not set/press "AC". I just turn temp **** to desired temperature and it kicks on AC or Heat as needed.
On my previous vehicles I would press "AC" to On when needed - but then shut off the "AC" before shutting off the engine.
I always thought I was saving additional load on the engine while starting with the AC compressor off and maybe saving excessive compressor wear also.
Will I cause more wear & tear by just using "AUTO" ?
YMMV,
MidCow3
Instructor
Joined: Jan 2023
Posts: 1,193
Likes: 675
From: Niagara Falls, Ontario
.And don't forget it works the opposite in winter. If you use the dash vents and not the floor it'll keep blowing hot air out the vents way too long for my liking as it waits to heat up the dash. I mix blend floor and dash or defrost and floor to get the dash warmed up quickest.
As an option you could direct air to nott blow right upon you but maybe up towards roof.
Last edited by TheCDN; Jul 20, 2025 at 01:16 PM.
Pole Position
Joined: Aug 2011
Posts: 2,035
Likes: 857
In your case set the air vents, fan speed, recirc, and temperature to you liking, but you can't program AUTO ...sorry YMMV,
MidCow3
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Pole Position
Joined: Dec 2012
Posts: 2,154
Likes: 967
From: Toronto, ON
Fan speed is usually a consequence of the temperature differential between the HVAC setting and ambient. If you want to adjust fan speed without disabling auto, simply adjust your HVAC setting a bit closer to ambient and the fan speed with reduce.
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