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96 Cavalier, 2.2L. I have a new AC compressor, accumulator and orifice tube installed in this vehicle. Trying to recharge Freon but compressor clutch won’t kick in. Rumor has it that either I have a leak or the Freon level is too low (mechanic). I have checked online in various places and cannot find the low pressure sensor or whatever it is called that makes the clutch kick in. Does anyone know specifically where it is on this vehicle? I have looked at Eric’s videos and the person that is helping me has decades of experience doing this. Relays and fuses check good, wires appear intact.
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You need to use a vacuum pump and pull a vacuum for 30 minutes to an hour to remove air and moisture, close the valves, and see if it holds the vacuum for at least 30 minutes. That is standard practice before a recharge anyway, and should not be skipped. This would also confirm whether or not you have a leak. After the vacuum is pulled and holding, there is sufficient pressure in the can combined with the vacuum, to cause a total pressure differential high enough to trip and engage the compressor so that the charge can go in.
I asked exactly Where the low pressure switch is that tells the compressor clutch to engage, not what you wrote.
You don’t have an external low pressure switch because you have a V5 variable displacement compressor.
ok, thank you. One of my mechanics said to ask you if that means that the compressor is shot? It is new, but even I know that means nothing.
Without actually being there I cannot say whether the compressor is good or not. If you are just having a hard time getting the charge to go in, that is no indication that the compressor is bad. Recheck all the work: make sure the proper amount and viscosity oil was installed in the compressor and receiver/drier (accumulator), make sure the high pressure cut-out switch from the rear of the old compressor was transferred to the new one (if the new one didn’t come with it–most don’t). Attach the manifold gauges and vacuum pump, evacuate and pull the vacuum down to 28-30 inches for at least 30 minutes, close it all up and see if it holds the vacuum for 30 minutes, and if so, then if the charge won’t go in, try jumpering the contact side (not the control/coil side) of the A/C clutch relay to engage the compressor. Be sure to purge air from charging hose. After a few ounces of refrigerant have been added, remove the jumper and reconnect the relay to let the system operate normally, and continue to charge. Variable displacement compressors are picky about being correctly charged. Make sure to charge by weight (ounces of refrigerant), not by pressure. The pressures are used to verify normal operation, not to measure the charge. Oil: PAG-150, 8 oz in compressor, 1 oz in inlet side of accumulator, 9 oz total. Refrigerant charge: R134a, 24 oz.
wow, double thanks! I don’t remember having to transfer a high side anything from old to new but maybe they told me to do that. Yeah, I guess this stuff is really finicky… I will see what happens later on after I rebuild this laptop.
Where would that switch have been located on the old compressor? It’s been long enough ago that I don’t remember if I was told to do it or not. All I remember is putting a 2 pin connector in the side towards the front plus the in and outbound Freon lines along with the mounting bolts. A picture sure would help but not abs necessary because I don’t even know what this thing looks like. I know where the high and low sides are for Freon and there is a 3 wire connector towards the passenger side of the high side port but I have no idea what that is for.
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