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Discussion Starter #1
Alright, my buddy and I installed a new ac system minutes the evaporator core. New lines, pressure switch, compressor, condenser, expansion valve. Did a vacuum for a hour, let it sit for a additional half hour to check for leaks. Didn't drop pressure at all. Go to add freon and the compressor won't cycle. Low pressure it's around 50 and high is at 40. I pulled the AC compressor relay from under the hood and over rid it with a paper clip just to see if the clutch would engage and it did. Put a brand new relay and still nothing. Replaced the 10 amp clutch fuse and nothing. And I only tried these things cause the pressure didn't change after trying to charge it for 20 minutes and the compressor wouldn't cycle and the pressure on high or low side wouldn't move. Any help would be greatly appreciated.
 

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It might be worth testing the pressure switch side of the system. If the system is sensing a pressure issue it would be unlikely to run.
 

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Discussion Starter #3
Thanks boomer. It turns out I had a issue with the little tool that punctures the refrigerant, it would puncture but wouldn't release. Weirdest thing. But now I got it charged and the Ac blew cold as ever. Got the low side around 35 and the high around 250. Worked great for a hour. Now the compressor won't cycle on its own. I hooked up the gauges and pressure was even at 120 on both sides before I override the compressor with a paper clip on the relay to make sure the compressor was getting current. It blew cold and had good pressure readings. But it won't work on it own when I put the relay back in. Replaced the relay, checked for current on uber fuse box side, all good. No leaks cause I have uv freon and checked all around and couldn't see anything plus the pressure holds good. Kind of lost now
 

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There may be others more familiar with that AC system. I believe you are supposed to refill by weight and there is a label on the front of the car telling you how much. Are you confident you added roughly the correct amount? 120 sounds high to me for static pressure. I thought it should be more like 80, but it does depend on the temperature in your area and there are charts to give you an estimate..

You have proved that the clutch works and the system will cool, so I would still be thinking on the input side of the system. Pressure switch, ac light on, cabin fan blowing. Hope you find it.
 

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What Boomer said. Find a schematic and trace the wiring to find where you lose the signal to turn on the compressor.
 

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Discussion Starter #6
Thanks everyone fit the guidance. I had my mechanic come out and I was not getting a ground signal from the computer/ac cabin button. So i ordered a new HVAC control unit. Should be here Thursday. If that doesn't fix it then I'm going to take it to a auto electrical specialist. I don't trust my skills in that area and don't wanna risk damaging anything.
 
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