AC low side at 100+ psi

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Habbibie

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Ok I'm confused here and would like some insight on this.

First off I have turned the AC on a few days ago and it was ice cold, fast forward to today (85 degrees outside) I start the truck up and turn the AC on to cool the interior down before I leave work, I left it running for 5 minutes and when I came back to it there was a very strong burning smell like that of burning plastic or rubber. I popped the hood open and noticed the AC clutch is semi engaging then it stopped all together. I shut off the AC which was now blowing hot air and the smell disappeared, I drove home and on the way I turned the AC on again but this time no smell, but still hot air though.

So I get home and I plug the gauge to the low side and it reads 125 PSI, this number does not change regardless of truck is on, AC on full blast, truck on AC off or truck off AC off, it still reads 125 PSI. If I press the trigger on the gauge it drops to 0 PSI and blows a very faint amount of oil maybe refrigerant hard to tell cause of how minimal it is.

So now I'm at a clueless point do I relieve pressure on the high side or what??

When it ran normally before it didn't act unusual or anything, it worked as it should

Matter of fact when I started the truck earlier the AC ran before I went back inside work,
 

stamp11127

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Don't release any of the refrigerant as it isn't overcharged, doesn't do the atmosphere any good and is a waste of money.

If the compressor isn't engaging the low and high side pressures will balance - this is referred to as "static pressure". In this case a low side pressure of 125 isn't abnormal. The smell you may have noticed is the compressor clutch coil burning up. You can use a meter to check the resistance of the coil or for a short to ground.

Once the clutch and compressor are working properly then you can diagnose any additional issues within the system.
 
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Habbibie

Habbibie

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Ok I did as you said, first I checked the fuses and the small 10A fuse was blown, I replaced it and the AC ran normal for about 5 seconds and blew the fuse again, so I crawled under the truck and sure enough ground is loose. Tightened it up and replaced fuse, worked again and remained on this time. I checked the pressure & it's a tad low but still useable.

Thank you for the help STAMP11127
 

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