A/C was working great and then suddenly stopped.Low pressure side is around 40psi until the clutch kicks in and then drops to around 5psi.Clutch cycles on and off every few seconds.Low pressure line gets cold when I bypass the low pressure sensor but still doesn't cool.No moisture dripping from the condenser either.Any help would be appreciated.Thanks.

Also the blower motor resistor was changed right before this issue came up.

2 Answers 2


You lost your charge. The low side should read about 30psi when ac is running. You'll need to look for a leak or have it recharged. Also alot of the newer vehicles have dye in the ac system from the factory to help look for leaks.

  • I do have refrigerant I could add.I'm not able to test the high pressure side pressure.Should I add some with the ac on and running until I get to 30psi?
    – Neil
    Commented Jul 31, 2017 at 0:45
  • Yeah, i am guessing its a r134a system and you have a can of freon and hose/gauge to install from the local parts house. There should be a tag under the hood somewhere thay tells the ac system capacity. Just follow the instructions. If this is the case.
    – cano
    Commented Jul 31, 2017 at 1:00
  • I will give it a shot tomorrow.Just keep reading about people overcharging the system.I don't want to be one of them.
    – Neil
    Commented Jul 31, 2017 at 1:20

Mr Niel, may you please share on what transpired with your issue? Your situation and symptoms are exactly what i am experiencing on my 2005 chevrolet silverado 1500. I added r 134 thinking that it lost charge and stopped adding r 134 prior to the 50 psi needle mark. After 50 psi is when the pressure gauge needle goes into yellow territory. I did not want to become the victim of overcharging. Im still experiencing the same issue difference being im getting a read of 50 psi when clutch is engaged and drops about 5 when not engaged.

Note: i changed the pressure switch sensor thinking that was the culprit only to find out that it wasnt the issue.

I greatly appreciate your feedback.

Thank you

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