BuzzLY37

iTrader: (2)

Hello all

I've tried to searched on my question but doesn't seem to get the complete answer. So hopefully you guys can answer them.

Do you guys keep your AC on all the time? Since you can adjust the temperature to either colder or hotter, I'm not sure whether I should just leave it on and adjust the temperature. I've had a non automated climate control car before and I've always had to keep turning the AC on and off as I drive and get out of the car. (My AC unit died after about 2 years so I've developed that habit.)


Sorry if my question is a bit silly. Any opinions appreciated.

ThanksDOMO

hispeed-lowdrag

iTrader: (7)

I keep mine on all the time and just change the temp slightly depending on the wx

TheLocNar

iTrader: (5)

I only turn mine on when it's 90+.

BuzzLY37

iTrader: (2)

Thanks for your opinions!

Do you guys know if the AC tend to have a shorter lifespan if you leave it on all the time?

evilpanda

I only use my a/c when needed. if its not that hot i'll leave it off or just tilt the sunroof for some air.

SkyMG37x

The AC light does not necessarily mean that the AC system is ON, i.e. it's also on in the winter. The AUTO Climate systems such as in this car use the various sensors to determine when to engage the compressor, and in some cases use a multi-stage system.

Bottom line, there's no reason not to just leave the system in AUTO and let the AC run accordingly. In fact if you check your owner's manual there's a comment about turning off the AC when the temp setting is lower than outside temp:
I just leave it in AUTO.

BuzzLY37

iTrader: (2)

Okay, that definitely clears up alot. Thanks SkyMG37x!

I guess I'll just leave the AC on from now on and adjust the temperature.

ged1067

Left in on my last car; doin the same with the G.

GED

SM_Shadowman

A/C button & light basically means it's dehumidifying. You'll notice it comes on in the winter also when it should be heating, which seems wrong but it's fine. You can turn it off if you want (when heating), but it doesn't really matter temperature-wise. Always want it on when defogging or cooling.

Basically, the manual says the A/C is used for "Cooling or dehumidified heating."


I think if the external temp is below something (like 30 degrees or whatever) it does not come on automatically.

indycase

The AC removes heat and humidity so if it is ON, the compressor will be on. That is why whenever you turn to defog, the AC comes on automatically. The manual tells you to not set the temperature lower than the outside temperature if the AC is off because without the compressor, the system cannot adequately cool down the interior to a temperature lower than that of the outside air. In other words, turn the AC on if you want to cool down or to dehumidify. However, it uses more gas to leave the AC on because it puts a tiny bit more load on the engine via the drive belts.

In my 2003 Maxima and my 2006 G35, there is an ECO button, which I no longer see on my 2010. What it does is it cycles the compressor on and off depending on the need to cool down the interior or not in order to reduce fuel consumption. I also notice that the AUTO RECIRC mode on the 2010 only operates when the AC is on, which I don't understand why because I do want the system to shut out outside pollutants/odours whenever these are detected but I may not necessarily want the AC. I swear I won't suffocate just because there is no fresh air coming in without having the compressor being turned on. LOL

BuzzLY37

iTrader: (2)

So would the compressor last less longer if I leave it on all the time? That's what happened in my old toyota. I just left the AC on all the time and eventually I had to have the compressor replaced. Big pain in the butt.

HappyG

I had my Maxima's AC on for over 10 years, it just kept going, never need compressor replacement.

SkyMG37x

That's not correct on AUTO systems. The ON light means the AC is enabled, but the HVAC head unit (computer) decides when to turn on the the compressor. In the winter the light is always on even though the compressor will not come on when the temperature is below 23F. This is how most auto HVAC systems work.

From Service Manual:



Also:

Unified meter and A/C amp. controls compressor operation by ambient temperature, intake air temperature and signal from ECM.

SYSTEM OPERATION

When A/C switch, AUTO switch, DEF switch or D/F switch is pressed, unified meter and A/C amp. transmits compressor ON signal to ECM, via CAN communication.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant-pressure sensor signal, throttle angle, etc.). If it judges compressor can be turned ON, it sends compressor ON signal to IPDM E/R, via CAN communication.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate compressor. When sending compressor ON signal to IPDM E/R via CAN communication line, ECM simultaneously sends compressor feedback signal to ECM via CAN communication line. ECM sends compressor feedback signal to unified meter and A/C amp., then, uses input compressor feedback signal to control air inlet.

Compressor Protection Control

When the high-pressure side detected by the refrigerant pressure sensor is either approximately 3,119 kPa (31.8 kg/cm

2, 452 psi) or more, or approximately 118 kPa (1.2 kg/cm2, 17 psi) or less, ECM turns the A/C relay OFF and stops the compressor.

Low Temperature Protection Control

Unified meter and A/C amp. turns compressor ON or OFF as judged by a signal detected by ambient sensor and intake sensor.

When ambient temperature is higher than

−2°C (28°F), the compressor turns ON. The compressor turns OFF when ambient temperature is lower than −5°C (23°F).

When intake air temperature is higher than 1°C (34°F), the compressor turns ON. The compressor turns OFF when intake air temperature is lower than −5°C (23°F).

BuzzLY37

iTrader: (2)

So since I don't live in an area that is usually below the freezing point, my compressor will always be on? Especially now it's summer.

Can you further confirm what's mentioned earlier that compressor being on majority of the time is not going to decrease the lifetime of the component?

Thanks

eksigned

iTrader: (1)

Just a side comment: I test drove a 2010 4Runner today, and the new RX350. Both systems didn't give off a very cold AC. I was mildly disappointed, but hey...neither of them will be my car...sooooo...haha

I thought our "cold running" AC system was the norm, but as it turns out...it isn't it's very true that our systems run very cold. It's a good thing...! I wonder if they run extra hot up top? I want to say no (used it once in the time of ownership so far...)