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Discussion Starter · #1 ·
2002 1500 4.7l, I was tinkering with the ac and it was blowing hot air, I didn't hear the compressor kick in once so I checked the fuses and fuse 16 (ac clutch) was blown so I replaced it, I checked the wiring best I could, I tried it again and waited about 8-10 minutes and it never tried to engage, I checked the fuses again and they were good, I tried checking the freon pressure and it didn't read anything, I did it while running and ac on full blast. I'm not really knowledgeable on ac systems but with my luck I'm thinking an new compressor, unless you guys know of anything else I should check out first. It sits right on top so it doesn't look too hard of a job but I know looks can be deceiving. Isn't the front of the compressor clutch supposed to spin when engaged? If it does mine doesn't, what do you guys think?
 

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Your truck has a low pressure cutout switch, if it gets to low on refrigerant it will shut off.
 

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Discussion Starter · #3 ·
Your truck has a low pressure cutout switch, if it gets to low on refrigerant it will shut off.
So should I try to add some refrigerant or should I do some testing on the high and low pressure ports first?
 

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If it is empty it will need some refrigerant to overcome the kick off pressure of the switch, sometimes you will need to add liquid to achieve this. Most likely you have a leak somewhere in the system that will need to be addressed otherwise you will be in the same situation . Get some refrigerant with leak finder in it ,you might be able to find that leak . Or save your money Up then find an independent mechanic to remedy this .
 

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50 PSI minimum if I remember for low pressure switch. If its that low, where did it go? You can just go forcing freon in as the "air" thats in there has to go somewhere. Thats why system needs to be in vacuum before service. And also gives you a way to check system is sealed tight. If it holds a vacuum for 30-45 min it probably will hold refrigerant.
 

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Discussion Starter · #6 ·
50 PSI minimum if I remember for low pressure switch. If its that low, where did it go? You can just go forcing freon in as the "air" thats in there has to go somewhere. Thats why system needs to be in vacuum before service. And also gives you a way to check system is sealed tight. If it holds a vacuum for 30-45 min it probably will hold refrigerant.
When I bought the truck he said engine had been replaced some time ago, so I'm thinking they may not have refilled the ac system, at least that's what I'm thinking, I can try a can of ac pro, I thought the ac gadge wouldn't give me a reading because the compressor wasn't kicking on, does it still give me a accurate reading without it kicking on?
 

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If the system is empty , then as djh3 said it absolutely needs to be evacuated. If you aren’t experienced with this someone who is should be the one to do the job. Also the dryer should be replaced.
 

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You can try to temporarily test it by unplugging the low pressure switch and briefly jumping the wires, the compressor should engage if everything else is working
 

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Discussion Starter · #9 ·
You can try to temporarily test it by unplugging the low pressure switch and briefly jumping the wires, the compressor should engage if everything else is working
Right on, I'll see about doing that this weekend
 

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Discussion Starter · #10 ·
If it is empty it will need some refrigerant to overcome the kick off pressure of the switch, sometimes you will need to add liquid to achieve this. Most likely you have a leak somewhere in the system that will need to be addressed otherwise you will be in the same situation . Get some refrigerant with leak finder in it ,you might be able to find that leak . Or save your money Up then find an independent mechanic to remedy this .
Well I tried adding a little refrigerant and I had everything on and ac on full and about 5 seconds into trying to refill it the high pressure hose popped, so does this mean it had refrigerant and it's another issue? Guess I'm buying another hose, glad the compressor and lines are easy to get to.
 
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