Air conditioner...ALWAYS on, Why?

[Nayov]

Why is the air conditioner designed to be always on?
I like my (old) Sentra because there is a separate switch, but the Frontier it always cycles except in the Foot position. American cars for quite a few years had this always-on feature and i guess imports are probably always-on now.

I suppose they did this for faster de-fogging, but if so, why not limit it to only the Defrost position? Better yet, the driver ought to be able to use the A/C when and if he wants.

Just think about this: We could save a LOT of fuel, collectively, if the A/C control were manually operated.

I know there is a frost sensor that shuts the thing down at temps below 40°F anyway, but still there is a substantial amount of time when it runs otherwise.

 

[Petrou]

i know its dumb. but they do that to keep the moisture out of the vehicle and off the windows

 

[KLowD9x]

Is it a "swash plate" compressor that is variable from some obscenely low number to 100% flow?

New Volvos have this and they "never turn off". In fact, they are off, it's just that the plate goes to the most flat position and almost no refrigerant is flowing.

I think they did it for longevity. The oil is always flowing through the system and the clutch doesn't wear out.

 

[wander2039]

Wire in a switch.. easy to do on my two vehicles I just haven't seen the need. Windows clear up much faster with the ac portion working.

 

[Bob Woods]

On some cars that will make the service engine light (mil) come on.

 

[StevieC]

My Santa Fe has a separate button to turn the compressor on/off.

 

[Warstud]

What you think is the AC could just be fresh air coming in through the vents. Check it while parked to see if it still blows air then switch the temperature control to see if it blows hot.

 

[Steve S]

It is better for the compressor to run . Think about hoe long a refrigerator lasts cause it is always running.

 

[KrisZ]

My car has an AC button as well, but floor and window defrost settings will turn the compressor on automatically. The compressor, however doesn't cycle as often and deosn't cool as much as with the button turned on.

 

[fsskier]

This has been a pet peeve of mine also, several of our cars ran the air conditioners in the defrost position. Others only run it when a separate demist position is selected.

Ever notice how many cars are being driven - in summer - with the windows down on nice days and you hear click, whirr, click, whirrr...... The have inadvertently left the lever in defrost (heck maybe from Iowa's last frost in May) and the compressor may cycle all summer long, even on the days they are driving around with the windows open!!

Surely this is wasting a lot of gas for the uninformed!!

 

[Max_Wander]

Years ago our car had an AC button and and Eco button. Without either on, the compressor would never come on. Now I think all AC systems operate on the "Eco" mode constantly. I understand keeping the compressor lubed and all, but that doesnt mean it needs to cycle on and off non-stop for the entire length of the drive. Perhaps it's purpose is to prevent a wet evaporator from re-humidifying the air- but then it wouldnt be wet with condensation to begin with if it never got cold in the first place.

 

[StevieC]

Originally Posted By: Steve S
It is better for the compressor to run . Think about hoe long a refrigerator lasts cause it is always running.
With me living in my car 8,10 sometimes 12 hours a day I have the compressor running a very long time. I have piled on 200K KM (120K miles) in just under 4 years so it has seen its workout for sure (Winter & Summer)...

"To keep something running forever, you need to keep it running forever"

 

[frankm]

Originally Posted By: Steve S
It is better for the compressor to run . Think about hoe long a refrigerator lasts cause it is always running.


Very true; most people don't run their a/c in the winter every few days like they're supposed to, then complain because they need a new $1500 compressor just out of warranty.
Also, the effect of the a/c compressor on gas consumption is very modest compared to the old days.

 

[robbobster]

Another pet peeve is the lack of a separate "recirc" button on domestics. The "MAX A/C" setting is usually recirc, but I like having a separate button if I drive through a stinky area.

 

[Greaser]

Pull the A/C clutch fuse and she'll stop.Replace it once in a while to keep things lubed.Done this for 10 years on my Jeeps.Can't stand running the air at -20.

 

[Pop_Rivit]

None of my vehicles have the air conditioner always on.

Quote:
It is better for the compressor to run . Think about hoe long a refrigerator lasts cause it is always running.


A refrigerator isn't subjected to the extreme temperatures and vibrations to which a vehicle is subjected. Take a refrigerator compressor out, put it in a car and I suspect it would have a failure rate just as high. Refrigerator compressors also aren't subjected to weight restrictions for fuel economy, so heavier materials can be used. Comparing it to the compressor in a vehicle isn't a realistic comparison.

Also, my refrigerator compressor doesn't always run. It cycles on an off and only runs a couple times each day.

 

[xxch4osxx]

Originally Posted By: robbobster
Another pet peeve is the lack of a separate "recirc" button on domestics. The "MAX A/C" setting is usually recirc, but I like having a separate button if I drive through a stinky area.

My Silverado has a seperate recirculate button, I use it alot, especially if I am about to enter a very dusty area!

 

[sciphi]

My 99 Buick has a "recirc" button. Also kicks on the compressor in "defrost". I like it doing that, except on cold mornings when the engine isn't warmed up yet.

 

[eljefino]

I'm with sciphi.

My car has "ram air" ventilation that I can't easily avoid. (I can activate AC to allow the recirc blend door to move then kill it.) I put it to defrost as the least bad option while it's warming up. Add AC to this mix (think 45-50'F) and the windscreen fogs: sometimes inside, sometimes outside.

My fix was a switch inline with one of the line pressure switches. I unplugged the connector first, and saw it disabled the compressor. Bingo!

 

[rshaw125]

Originally Posted By: fsskier
This has been a pet peeve of mine also, several of our cars ran the air conditioners in the defrost position. Others only run it when a separate demist position is selected.

Ever notice how many cars are being driven - in summer - with the windows down on nice days and you hear click, whirr, click, whirrr...... The have inadvertently left the lever in defrost (heck maybe from Iowa's last frost in May) and the compressor may cycle all summer long, even on the days they are driving around with the windows open!!

Surely this is wasting a lot of gas for the uninformed!!

I do the same thing to my 4 cars in October. All 4 have their AC fuses pulled. I put them back in in April. I started doing it when I noticed my daughter was driving with the system set to defrost. The AC was kicking in and out. When it was a gorgeous 75 degrees out.