Car Air Conditioning Question

[Fordnandez]

I have done a little research on line about his but I am kind of getting some conflicting information so I figured I would reach out to the green screen.

Here is the issue I have in my 00 suburban that is my lease vehicle. I get air through the vents but it is not cold. The AC button is on but the compressor clutch never engages. I have one of those AC Pro charge kits and when I hook up the gauge to it it reads zero pressure. My question is if the compressor is not running should there be any pressure on the low side port? I would assume there is but this is what I am getting some conflicting information on.

It is my understanding that if there is low pressure the compressor will never come on. Looking back on it I should have just put in the can I had with me to see if it would get the compressor to kick on but I didn't. I wasn't too thrilled about wasting a 25 dollar can of refrigerant but at the time I thought I had an issue with the compressor clutch not engaging.

Any help would be appreciated.

[miket]

Not a pro, but have done a little bit. If there is no refrigerant in it then it will read 0 without the compressor running. If you really are at zero I would evac the system before doing anything else

[airehead]

There is a low pressure switch in the suction line that will not allow the compressor to run if the pressure is below the setpoint.
If you put a gauge on it and it reads zero that means there is no pressure you should first Find the leak in the system and fix that And then evacuate the air and noncondensibles from the system then fill it with refrigerant

[Fordnandez]

Thanks for the reply. Like you said now that I have some time to think about it I am pretty confident that it was out of refrigerant and I probably have a leak which I am not too thrilled about....... I just wanted to confirm that the only way it would show pressure is if the compressor is on. I think there should be some pressure there even when it is not running.

[miket]

Also, if you dont know if/where the leak is, add some refrigerant or vaccum and check for leaks at the valve. The valves in that era vehicles leak when they get old. Easy fix, but will need to evac the system after doing it. If you charge with air ion the system it will be nothing but trouble. Air equals moisture. moisture equals acid. Acid ends up killing compressors, coils etc.

[Fordnandez]

There is a low pressure switch in the suction line that will not allow the compressor to run if the pressure is below the setpoint.
If you put a gauge on it and it reads zero that means there is no pressure you should first Find the leak in the system and fix that And then evacuate the air and noncondensibles from the system then fill it with refrigerant

Thank you for your reply.

[miket]

Thanks for the reply. Like you said now that I have some time to think about it I am pretty confident that it was out of refrigerant and I probably have a leak which I am not too thrilled about....... I just wanted to confirm that the only way it would show pressure is if the compressor is on. I think there should be some pressure there even when it is not running.

If I remember right the pressure on a R134 system when not running is like 35psi.

[Fordnandez]

Also, if you dont know if/where the leak is, add some refrigerant or vaccum and check for leaks at the valve. The valves in that era vehicles leak when they get old. Easy fix, but will need to evac the system after doing it. If you charge with air ion the system it will be nothing but trouble. Air equals moisture. moisture equals acid. Acid ends up killing compressors, coils etc.

The valve you are talking about is inside the two pressure ports correct?

[kruppa24]

There is a low pressure switch in the suction line that will not allow the compressor to run if the pressure is below the setpoint.
If you put a gauge on it and it reads zero that means there is no pressure you should first Find the leak in the system and fix that And then evacuate the air and noncondensibles from the system then fill it with refrigerant

This^^^^^^^^^^^^^^^

[miket]

The valve you are talking about is inside the two pressure ports correct?

Yes. Pretty easy fix, some you just get a little schrader valve removal tool and unscrew, some you replace the whole little aluminum body. Just make sure there is no pressure in the system first

[Fordnandez]

Thanks for all the help gentleman.