Air conditioner pressure switch

2003 LEXUS RX 330
124,562 MILES • 6 CYL • 2WD • AUTOMATIC
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BLESSING EWOBOR
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Hi, I am working with the vehicle listed above, its air conditioner is not working. The compressor is not responding to the switch. I have tested somethings like relay and fuse. I want to test the pressure switch, but it has four wires unlike the ones with two wires that one can easily by pass. In this case how will I test the switch or by pass the switch with four wires?
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Sep 3, 2020 at 4:58 AM
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ASEMASTER6371
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Good afternoon,

Do you have a set of gauges to check the Freon pressure? That switch needs pressure to close to turn on the compressor.

I attached a wiring diagram for you to view. You will need a voltmeter to do some testing for the switches. There is a high side switch and low side switch in the same pressure sensor.

https://www.2carpros.com/articles/how-to-check-wiring

Roy
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Sep 3, 2020 at 12:50 PM
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BLESSING EWOBOR
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Thank you,

Sir, is that the full diagram? from the diagram you sent? it seems that something is missing in between for instance, for the second diagram, there's a yellow wire coming from the Diode(A/C)(behind upper left side of dash) did not reflect on first diagram and the wire numbering start from 6 at the extreme left on the second diagram. I can't find 2,3,4,5 on the first .
Sep 3, 2020 at 9:38 PM
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ASEMASTER6371
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Yes, it is. The first is the top of the diagram and the second is bottom of the diagram.

Print them out and put them together.

Roy
Sep 4, 2020 at 3:52 AM
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BLESSING EWOBOR
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Thank you sir.
Sep 4, 2020 at 7:34 AM
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ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
Sep 4, 2020 at 7:41 AM
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BLESSING EWOBOR
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Hi, from the article ""https://www.2carpros.com/articles/how-to-check-wiring", which talks about how wire can be checked and tested. The illustration used was camshaft position sensor and the engine ECU (both of them are in the engine compartment), the resistance on the wire between the sensor and the ECU was tested by connecting the meter, probe at both ends.
What if the engine ECU is in the vehicle (under the dashboard) how can the resistance of the wire between the sensor and the ECU be tested?
Sep 5, 2020 at 8:33 PM
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ASEMASTER6371
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You will need long cables to attach to each end. You can get a set of jumper wires at a parts store for this test.

Roy
Sep 6, 2020 at 4:04 AM
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BLESSING EWOBOR
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Lol, thank you.
Sep 6, 2020 at 7:43 AM
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ASEMASTER6371
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You are welcome.

Roy
Sep 6, 2020 at 7:55 AM
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BLESSING EWOBOR
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Good morning, please could you help me with diagram that will include " FAN 3 RELAY"? I want to use it.
Oct 19, 2020 at 7:01 PM
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BLESSING EWOBOR
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From the diagram, For the A/C Triple pressure switch, the terminal that labelled 1, is it supposed to be five volts since it is coming from the engine control module?
Oct 19, 2020 at 7:06 PM
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ASEMASTER6371
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Okay, I reattached the wiring diagram for you to view.

The pressure switch is 12 volts, not 5. Sensors have 5 volts and switches are 12 volts.

Check the fuse for relay number 5 in the diagram for power on both sides.

Roy
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Oct 20, 2020 at 1:28 AM
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BLESSING EWOBOR
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Thank you.
Oct 22, 2020 at 9:43 AM