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I have a 2014 Lexus RX350 that doesn't blow cold air. The clutch never tries to engage on the compressor and the condenser fan never runs. Static pressure was about 100 psi (the garage was 85' f) on both the low and high side. I removed the clutch coil relay and jumped it out to force the clutch to pull in. The compressor clutch engaged, but I got no change in pressure on the high or low side (the condenser fan never came on either). After shutting of the motor, I can spin the clutch with one finger with no resistance.

I'm thinking I may have a bad compressor, but I'm also concerned with the fact the system isn't even calling to kick on. Am I looking at this right and should I replace the compressor?

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  • Welcome to Motor Vehicle Maintenance & Repair! The pressure seems low, even equalized. With low pressure, it will never send the signal to engage the compressor on its own. It sounds as though the clutch kicks in (being forced on) and pushes the compressor around. When the engine is off, the clutch is disengaged, so if there's no belt on it, it will spin over without any resistance. Commented Feb 17, 2022 at 18:03
  • When you jumped the relay, can you hear the clutch pull in? Do you see more of the compressor shaft start to spin? Often you can see just the pulley turning with the clutch disengaged, then you can see the compressor shaft turn when the clutch engages.
    – HandyHowie
    Commented Feb 17, 2022 at 22:04
  • Usually the low pressure switch cuts out around 30 psi, so compressor should start but if you are low on gas the pressure on the low side will drop which will cause the compressor to turn off. You then get the compressor turning on and off repeatedly.
    – HandyHowie
    Commented Feb 17, 2022 at 22:08

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No change in pressure from low to high with the compressor running, the clutch engaged, generally means the compressor is trashed. Even with something dramatic, like the orifice tube plugged, you should get a differential in pressure. If you can spin the actual compressor with your finger, that is another indication that the compressor has failed. The compressor should have some resistance, some friction.

In general, I like to get rid of the things I know are wrong and see what's left. If the compressor really did fail, it is likely it will have contaminated the system with metal from the compressor. You should flush the system with A/C flush and shop air, replace the receiver or dryer, replace the orifice tube and install a new compressor.

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