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cold weather - is it related to AC compressor clutch and/or system pressure?

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cold weather - is it related to AC compressor clutch and/or system pressure?

Old January 4th, 2018, 10:47 AM
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Default cold weather - is it related to AC compressor clutch and/or system pressure?

2001 cavalier 226K

The place I live is in the middle of the longest sustained extreme cold temperature stretch in a hundred years if you believe the news. As a result, I had to get on my head upside down and flip the broken vent selector under the glove box from open to closed. That unfortunately means that the inside windows get badly fogged up unless I turn the compressor and/or defroster on - which I usually don't do during the winter. It has been around 10 degrees every night for the past few nights and hasn't got above about 28 during each day - so this is record-setting for the 17 years I have had the car. When I went to turn the compressor on last night, I could tell immediately it didn't kick on because of the fogging up of all the windows - that forces me to keep the windows open all the time while driving which is unpleasant as you can imagine. I popped the hood and when the green AC light is lit-up (either by my or by turning the defrost setting on), the fan and compressor have always kicked on - except when either the fan relay or the fan motor had died (both of which I replaced years apart from each other). But now, not only is the fan not running but the AC clutch did not engage either. Now let me just say that I know the system was low on r134a over the summer but made it through the summer without adding any more, figuring I would re-asses the situation in the spring. So my questions are:

- I have read elsewhere that the AC will not engage if temperatures are extremely low for extended periods. Is this true?
- How can I find out if the pressure switch is doing its job and that the system is too low on refrigerant for it to kick on - if the compressor isn't running for me to check or add r134a in the first place?
- Where is the pressure switch (the one that would be the one either broken or working, depending on what the problem is) located and how hard is it to test?
- Is the cooling fan downstream of the compressor - in other words, since my cooling fan is not coming on when the AC is turned on (green light on) on the dash selector - would that be explained and fixed by diagnosing the compressor clutch issue - or am I looking at two different problems? If it was not 10 degrees outside, I would just let my car sit and get hot enough to have the fan turn on but that will never happen with it this cold outside.
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Old January 4th, 2018, 12:22 PM
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Originally Posted by Bozo View Post
2001 cavalier 226K

The place I live is in the middle of the longest sustained extreme cold temperature stretch in a hundred years if you believe the news. As a result, I had to get on my head upside down and flip the broken vent selector under the glove box from open to closed. That unfortunately means that the inside windows get badly fogged up unless I turn the compressor and/or defroster on - which I usually don't do during the winter. It has been around 10 degrees every night for the past few nights and hasn't got above about 28 during each day - so this is record-setting for the 17 years I have had the car. When I went to turn the compressor on last night, I could tell immediately it didn't kick on because of the fogging up of all the windows - that forces me to keep the windows open all the time while driving which is unpleasant as you can imagine. I popped the hood and when the green AC light is lit-up (either by my or by turning the defrost setting on), the fan and compressor have always kicked on - except when either the fan relay or the fan motor had died (both of which I replaced years apart from each other). But now, not only is the fan not running but the AC clutch did not engage either. Now let me just say that I know the system was low on r134a over the summer but made it through the summer without adding any more, figuring I would re-asses the situation in the spring. So my questions are:

- I have read elsewhere that the AC will not engage if temperatures are extremely low for extended periods. Is this true?
- How can I find out if the pressure switch is doing its job and that the system is too low on refrigerant for it to kick on - if the compressor isn't running for me to check or add r134a in the first place?
- Where is the pressure switch (the one that would be the one either broken or working, depending on what the problem is) located and how hard is it to test?
- Is the cooling fan downstream of the compressor - in other words, since my cooling fan is not coming on when the AC is turned on (green light on) on the dash selector - would that be explained and fixed by diagnosing the compressor clutch issue - or am I looking at two different problems? If it was not 10 degrees outside, I would just let my car sit and get hot enough to have the fan turn on but that will never happen with it this cold outside.
I dont live in cold country, so my knowledge of what the A/C system does at freezing temps is limited. I am pretty sure the A/C does shut down at 32 F to 39.F.
Some say its becuase the oil doesnt lubricate well at low temp, others because the A/C doesn't work well at low temps. Frankly I reall dont know to be honest.

You could bypass the compressor clutch with some 12 DC line, but it might cause damage. A cheap alternative would be to buy a small heater blower, usually
found at truck stops. Plugs into the lighter or power port and it doesn't care when the temp outside is: Here is one sold on Amazon:

Amazon Amazon

Last edited by oilcanhenry; January 4th, 2018 at 12:25 PM.
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Old January 4th, 2018, 1:02 PM
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Just unplug the power to the clutch
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