Weird A/C Problem
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Joined: May 2019
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From: California
Weird A/C Problem
Hi guys! I have a 2001 Lexus LS 430 UL and my A/C is having weird problems. When the engine's RPM is low, the A/C compressor would disengage and the A/C button would blink. But pressing the button twice would restart the compressor, blowing cold air as if nothing was wrong with it. When the RPM is high, the A/C works as it should. My OBD scanner showed no error codes and the A/C self diagnostic program also showed no current error codes. What could be the problem?
Pit Crew
Joined: Nov 2009
Posts: 102
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From: NM
It could be a low charge of refrigerant. The compressor disengages if it doesn't see enough high side pressure. At higher rpm it's able to keep the pressure up. It could also be high pressure switch out of tolerance or problem with the orifice tube.
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From: California
Thanks for your reply! Actually I had a mechanic check the A/C system and he did not find anything wrong with the system. There is no leak and he recharged the system with the adequate amount. The pressure switch was replaced 3 months ago so it is not likely to fail. I will check the orifice tube to see if there is any problem.
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From: California
Last update on the issue, I replaced the A/C compressor magnetic clutch relay with a new one I bought from Autozone and the problem goes away. The new relay's name is Duralast relay #20382 and I wonder if anyone has used such relay on their LS 430. Would it be okay for me to use it?
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Lead Lap
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Do you have a trusty worthy Independent mechanic or A/C shop to diagnose it for you or you could go to the dealer and for a one time diagnostic fee (usually $100 and change) they should point you in the right direction. You don't want to throw parts at an old car to try to find out what's wrong. Good luck and let us know how you make out. PS....Not too much on this forum with A/C issues for the LS430.
If the A/C is running you will get water from condensation on the evaporator coil draining out under the car. If your evaporator coil is frozen you will notice reduced airflow from the system.
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I just added some gas to fill the system up. Also, the reason why I filled the system up is that I thought my A/C problem was not related to the level of refrigerant, so filling it up should not affect anything, turns out I am wrong. I actually reduced the amount of refrigerant on purpose when I replaced the relay, because I saw from another website that someone solved their A/C problem when they took some refrigerant out. Up to now, I still have not figured out why replacing the relay and taking some refrigerant out of the system would work, but it did work.
I just added some gas to fill the system up. Also, the reason why I filled the system up is that I thought my A/C problem was not related to the level of refrigerant, so filling it up should not affect anything, turns out I am wrong. I actually reduced the amount of refrigerant on purpose when I replaced the relay, because I saw from another website that someone solved their A/C problem when they took some refrigerant out. Up to now, I still have not figured out why replacing the relay and taking some refrigerant out of the system would work, but it did work.
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I took the car to both my mechanic and local dealer lately and got different results. The mechanic made sure that the system had no leak and every component of the system, like A/C compressor and evaporator, was replaced around a year ago, but they could not find the reason why the compressor keeps kicking off. The dealer said it was the compressor but they were not sure if it was the root problem. Currently the system works fine but I discovered that when the engine's RPM drops below 600, the compressor would kick off. Now I am considering if there is a way to keep the RPM above 600 so to make the system work.