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2007 GT500
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Discussion Starter · #22 ·
It has more to do with monitoring compressor pressures while the engine is running than fault codes.
Yeah I figured it would either give a pressure reading or something abnormal or no input at all to indicate a fault. The compressor is not coming on so the pressures are about equal 25 to 30 low and high side from the manifold gauge set I connected. I didn't want to jump the relay with the car on to force the compressor on because I don't want to mess the compressor up.
 

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2021 GT 500
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When I attempted to charge it ambient temp was about 60 degrees. Not sure if that makes a difference.

Which switch should i change the pigtail? the low pressure 3 pin switch in the front or the ac clutch cycle switch between the engine and firewall that's almost impossible to get to.
I doubt you got hardly anything in it if it was 60. When the compressor isn’t running, the only way for refrigerant to flow into an already pressurized system is for the can to be at a higher pressure than the car.

I would start with checking the nearest switch to the oxygen sensor where you said you might have snagged the harness.
 
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Yeah I figured it would either give a pressure reading or something abnormal or no input at all to indicate a fault. The compressor is not coming on so the pressures are about equal 25 to 30 low and high side from the manifold gauge set I connected. I didn't want to jump the relay with the car on to force the compressor on because I don't want to mess the compressor up.
What was the ambient temperature when you saw 25 PSI on both sides of the system? Unless it was very cold, you almost certainly are low on refrigerant.
 
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Discussion Starter · #25 ·
Ac is now working! I brought it to a friend's shop to evacuate the system and remove any moisture and run a leak test. Then fill with correct charge. No leaks on test but only 2oz came out of the system. Which is confusing because there is no leak. It turns out it was just a coincidence with when the ac decided to stop working from low charge. I didn't disrupt anything when swapping the o2 sensor.
 

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Go figure that. At least you stayed open to the possibility that it wasn't related. I have gone down one too many rabbit holes convinced it was related to some other part/install only to later realize that it was just coincidence. Glad you got it resolved!
 

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Ac is now working! I brought it to a friend's shop to evacuate the system and remove any moisture and run a leak test. Then fill with correct charge. No leaks on test but only 2oz came out of the system. Which is confusing because there is no leak. It turns out it was just a coincidence with when the ac decided to stop working from low charge. I didn't disrupt anything when swapping the o2 sensor.
Strange that you couldn’t find a leak source. You lost a lot of refrigerant.

I guess it’s possible one of your pressure switches was leaking and changing them fixed the leak without you knowing it. I’ve seen those leak on numerous occasions. I even had one blow apart on me while driving. That made a hell of a mess. There was a big white cloud of Freon and refrigeration oil all around my truck. Lol
 
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Discussion Starter · #28 ·
Car was garage kept and no sign of freon loss on the floor or allover anything. I'm thinking you may be right that it was maybe a slow leak at one of the switches I replaced. Car is 15 years old and who knows how long it's been leaking or if the ac has ever been recharged. Thanks for the help everyone!
 

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Car was garage kept and no sign of freon loss on the floor or allover anything. I'm thinking you may be right that it was maybe a slow leak at one of the switches I replaced. Car is 15 years old and who knows how long it's been leaking or if the ac has ever been recharged. Thanks for the help everyone!
Glad you got it fixed.

FYI: Freon, refrigerant 134a in your case, is a gas at atmospheric pressure. It’s only a liquid at extremely low temperatures at atmospheric pressure or high pressure inside the system. There will be no visible signs of a small leak or pooling of liquid unless you’re in Antarctica when you’re looking for leaks. Lol With large leaks, you can get refrigeration oil accumulation around the leak site, but even then you usually won’t see any signs on the floor except maybe a drop of oil.
 
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