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Skyvisions, ASE Certified Technician
Category: Toyota
Satisfied Customers: 14461
Experience:  Toyota Master Diagnostic
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RX 330 Lexus: 2005 lexus RX330 3.3L What controls the a/c

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2005 lexus RX330 3.3L What controls the a/c compressor. the a/c compressor keeps shutting down.. Charged with freon to specs but still same thing.
Thank you for choosing JustAnswer and allowing me to help you resolve your Toyota questions! Does the light for the AC switch start the flash at any time?
Customer: replied 4 years ago.

Yes. Once it stats flashing i know the compressor is off

This system uses a solid-state relay for the magnetic clutch system. It is incorporated the fuse block under the hood. The magnetic clutch relay turns the magnetic clutch on when required. Either the solid-state relay is failing inside the fuse block which is not a good sign or magnetic clutch itself is not holding or the belt a slipping. The only other possible option would be if the rotational speed sensor in the computer is sending an erratic signal back to the computer then it will shut the system down. There are multiple things that can cause this. This is not likely a fuse related issue. The first step would be to check the connector at the magnetic clutch itself on the compressor. Then the only real correct way to check the sensor in the compressor is with an oscilloscope. You need to monitor the sine wave to see if it's consistent. There is no real easy steps to diagnose this. If you put a jumper wire to the black wire with a yellow tracer at the connector going to the magnetic clutch on the compressor then to the positive battery terminal and the compressor seems to run normally and it blows cold air consistently then this would probably rule out anything mechanical in the compressor. If you monitor the voltage on the black wire with a yellow tracer and it constantly has 12 V and the compressor is still kicking out this would indicate a problem with the magnetic clutch or the compressor itself. This would rule out any electrical problem with the solid-state magnetic clutch relay.
Customer: replied 4 years ago.

Oscilloscope. Would i wrap the pick up clamp around the black yellow wire?

No, that is the wire going to the magnetic clutch. The AC lock sensor uses the white wire with a blue tracer. This is pin number one. That is the input to the engine control computer. The Brown wire is the ground reference or the ground side of the lock sensor in the A/C compressor. You would want to monitor the white wire with a blue tracer on the oscilloscope.
Customer: replied 4 years ago.

Thank you for all that info... I'll put it to practice. You deserve an excellent rating.

You are welcome please don't forget to rate the question. If you need any additional assistance feel free to reply and I will get back to you.
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