# AC compressor turning on and off?!



## svasica (Jul 22, 2004)

My AC is turning on and off, most notably when the car is stopped, the AC will turn off/stop working (warm air will start coming out). Then, when I start moving, the AC will get cold again. I believe the compressor is turning off for some reason. I made sure the system is charged (not overcharged, the guage is in the middle of the blue section on the guage). Why would this be happening?


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## itchspecv05 (May 2, 2005)

What is happing the freon in your ac system is low which means your low pressure switch in the ac system is doing its job . It's turning on and off , when pressure builds up the compressor come on .


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## svasica (Jul 22, 2004)

I really don't think thats the problem because like I said in the post I checked the pressure in the system with a guage and it is within spec's. Actually, when I charged the system a week ago with freon, I kinda overcharged it, and when I did the compressor was doing just what you say, but probably because to much pressure was building up and not because there wasn't enough. I then let some freon out so the pressure dropped and then the AC started working...but i'm still having this little problem of the compressor turning off when I stop.


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## Biscuit (Mar 5, 2005)

Have you noticed any shaking or anything like that? My Honda shimmys like a bish at a stop with the a/c then eventually turn off on high pressure...seems to be a condensor fan. So check your con. fan and make sure its coming on when you have the a/c on.


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## Zac (Mar 10, 2004)

how are your belts?


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## svasica (Jul 22, 2004)

Yea, my fan comes on when the AC turns on. 

My belts are good.


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## svasica (Jul 22, 2004)

I'm gonna bring this post back to life since its still happening....is this a common problem on these cars?


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## 2ndb18 (Oct 24, 2004)

not a common problem, take it to a tech for some on car diag. its too hard to tell you whats wrong withought being there


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## SiL200SX (Nov 23, 2005)

to tell you the truth i think the compressor might need to be replaced..

my b14 does exactly that and i had it recharged, and the mechanic told me if it still does it that i should look into seeing if the compressor is bad


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## SPEEDO (Jun 9, 2003)

you could have a bad pressure switch!


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## Matt0470 (Jul 3, 2006)

My AC is turning on and off, most notably when the car is stopped, the AC will turn off/stop working (warm air will start coming out). Then, when I start moving, the AC will get cold again. I believe the compressor is turning off for some reason. I made sure the system is charged (not overcharged, the guage is in the middle of the blue section on the guage). Why would this be happening?

I'm having this exact same problem with my 2000 Altima. I also guaged the pressure and got a good reading. Did you try the pressure switch?


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## rps180 (Aug 20, 2005)

What year is your Sentra? You need to have a AC gauge hooked up at the time that the problem is happening to see exactly how high the pressure is getting in the system.
It doesn't matter if the pressure is shown as OK while sitting still. If you got some sort restriction in the line, it may exhibit the symptom you are explaining.
Also, are you sure that the freon you used is the correct one? Not the store bought kind you can add with a can? Some of those contain the wrong kind of oil and aren't quite compatible.
Another thing is the ECM, or the engine control module. Some Sentras the ECM sends the AC signal to the compressor. I have seen a couple of Sentras with bad ECMs causing the AC to not work properly.
Overheating will also create the same symptoms. If you are just sitting there and the fan isn't working, car starts overheating and the AC stops working. Once you start moving, car starts to cool properly and the AC starts working. (thats just a quick explaination)
But like someone said earlier, you need to have it properly diagnosed with the proper equipment. There is just too much information missing here.


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## Cynthia Frontier (4 mo ago)

svasica said:


> I'm gonna bring this post back to life since its still happening....is this a common problem on these cars?


Did you ever find out what it was? My 2015 is doing the same thing, except it will do it anytime..at a stop or flying down the hiway. usually it will come back on withing a few minutes but couple times it been out over 30 minutes.


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## VStar650CL (Nov 12, 2020)

Cynthia Frontier said:


> Did you ever find out what it was? My 2015 is doing the same thing, except it will do it anytime..at a stop or flying down the hiway. usually it will come back on withing a few minutes but couple times it been out over 30 minutes.


Yours sounds more like a bad TXV Valve which is turning your evap into a block of ice. Turning the system or the car off for a few minutes melts some of the ice and lets it start working again.


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## antoninomubarik (3 mo ago)

svasica said:


> My AC is turning on and off, most notably when the car is stopped, the AC will turn off/stop working (warm air will start coming out). Then, when I start moving, the AC will get cold again. I believe the compressor is turning off for some reason. I made sure the system is charged (not overcharged, the guage is in the middle of the blue section on the guage). Why would this be happening?
> Kodi nox​


seems to be a condensor fan. So check your con. fan and make sure its coming on when you have the a/c on.


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## Shade Tree Squatting (3 mo ago)

svasica said:


> My AC is turning on and off, most notably when the car is stopped, the AC will turn off/stop working (warm air will start coming out). Then, when I start moving, the AC will get cold again. I believe the compressor is turning off for some reason. I made sure the system is charged (not overcharged, the guage is in the middle of the blue section on the guage). Why would this be happening?


What are the pressures reading, high and low?


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## Shade Tree Squatting (3 mo ago)

antoninomubarik said:


> seems to be a condensor fan. So check your con. fan and make sure its coming on when you have the a/c on.


Clean the condenser with water, not really high pressure! Cooling fans on condenser running at high speed?Sun sensors can cause this problem as well as the compressor controller.


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