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Discussion Starter · #1 ·
I have IS 300 2004. Last weekend change out radiator, belt, and compressor. Monday my AC light started flashing about 5 after having the AC on. So I order a new AC relay. Today first drive with new relay now it takes maybe 15 minutes before my lights starts flashing. Any ideas what it could be?
 

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The flashing AC light is usually for a compressor lock DTC. Does the AC work, then cut off once the light starts flashing, or does it not work at all? Was the relay new, and the correct part number?

When the ECM is requesting that the AC clutch relay be turned on, but does not see RPM from the compressor, it assumes it is locked. You either have a faulty compressor, bad clutch relay, or bad mag clutch ground (on the compressor). Of course there could be other faults, but those are the most likely.
 

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Discussion Starter · #3 ·
The flashing AC light is usually for a compressor lock DTC. Does the AC work, then cut off once the light starts flashing, or does it not work at all? Was the relay new, and the correct part number?

When the ECM is requesting that the AC clutch relay be turned on, but does not see RPM from the compressor, it assumes it is locked. You either have a faulty compressor, bad clutch relay, or bad mag clutch ground (on the compressor). Of course there could be other faults, but those are the most likely.
The AC does work, well until it starts flashing than the air isn't cooled any more. All the parts I put on were new. I bought the compressor from rockautodotcom and the relay from lexuspartsnowdotcom. I will have to go double check all the part numbers.

I did notice today, AC didn't seem to start blinking until the engine RPM were under 1000 or when I was sitting at a light. But that could of been a coincidence.
 

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I have the same exact problem. Which compressor from rock auto did you use? I purchased the compressor kit and installed everything but the expansion valve. My compressor only shuts off when returning to idle.

I'm going to try a new relay, I'll let you know if that works, which would mean yours is probably faulty.
 

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Discussion Starter · #5 ·
it was the kit "GPD 7511680" and I did the same thing I didn't install the expansion valve. My old relay was 90987-02012 and the new relay I got is 90084-98031 but that didn't fix my problem. I guess this weekend I'm changing the expansion valve. Is there a way to test the clutch on the compressor, maybe rock auto sent out a few bad compressors
 

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Erice, that's the same kit and method I used so we have the same compressor.

I just got off the phone with an AC specialist who, after hearing what the problem is, pretty much concluded that it's the relay. The relay that I got was from the parts store here; the specialist said there's a specific one that's needed and that you have to go through Lexus. I'm looking into it more, and I'll let you know what I find, but I don't think the compressor is bad, nor does it sound like this is an expansion valve problem.
 

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Discussion Starter · #7 ·
Erice, that's the same kit and method I used so we have the same compressor.

I just got off the phone with an AC specialist who, after hearing what the problem is, pretty much concluded that it's the relay. The relay that I got was from the parts store here; the specialist said there's a specific one that's needed and that you have to go through Lexus. I'm looking into it more, and I'll let you know what I find, but I don't think the compressor is bad, nor does it sound like this is an expansion valve problem.
Ya let me know if that fixes it. I don't think it the compressor either but until its working right everything is a suspect.
 

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It wasn't the relay. There's another one of those relays in the box by the battery; I swapped them out and still had the problem.

It's at a specialist shop right now. I talked to them Friday and he told me that there's some resistance reading wrong. He's getting the old compressor brought over to put a part that is on it(that didn't come on the new one) on the new one to make sure that fixes it.

You may want to get in touch with whoever did your compressor job to get that part.(I'll let you know what the part is when I talk to him next) I think he said it's about 100 bucks from Lexus, and I'm not sure you can get it elsewhere.
 

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Discussion Starter · #9 ·
It wasn't the relay. There's another one of those relays in the box by the battery; I swapped them out and still had the problem.

It's at a specialist shop right now. I talked to them Friday and he told me that there's some resistance reading wrong. He's getting the old compressor brought over to put a part that is on it(that didn't come on the new one) on the new one to make sure that fixes it.

You may want to get in touch with whoever did your compressor job to get that part.(I'll let you know what the part is when I talk to him next) I think he said it's about 100 bucks from Lexus, and I'm not sure you can get it elsewhere.
Thanks for keeping me updated. I did my own work with the compressor and still have the old one. When I did the job I used the Shop Manual for the step by step how to do it but there was a part for disassembling the Magnetic Clutch that i skipped thinking I didn't need too because it was a new compressor. But that's what i get for assuming. I should go back and reread that.

Ya please let me know what part you switch
 

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Clutch Lock Sensor

Good news! I got my car back today and it seems to be running right.

Since you did the work yourself you'll remember the location of the sensor plug on the compressor. There's a small bolt holding the sensor on(on the bottom side of the compressor when installed) That's the clutch lock sensor, and it's responsible for shutting the compressor off at very low RPMs(if I understand correctly). Since we bought the same compressor kit from Rockauto, I'm confident that replacing the sensor on your new compressor with the sensor from the old compressor will solve the problem!

Due to the location of the sensor though, you have to empty the system. Removing the sensor will open the system and it won't be fun if you haven't previously emptied.

Apparently the Clutch Lock Sensor on the Denso compressor from RA is Japanese, and even though the outputs read the same, swapping them out solved the problem. I'd give it a shot.
 

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Discussion Starter · #11 ·
Good news! I got my car back today and it seems to be running right.

Since you did the work yourself you'll remember the location of the sensor plug on the compressor. There's a small bolt holding the sensor on(on the bottom side of the compressor when installed) That's the clutch lock sensor, and it's responsible for shutting the compressor off at very low RPMs(if I understand correctly). Since we bought the same compressor kit from Rockauto, I'm confident that replacing the sensor on your new compressor with the sensor from the old compressor will solve the problem!

Due to the location of the sensor though, you have to empty the system. Removing the sensor will open the system and it won't be fun if you haven't previously emptied.

Apparently the Clutch Lock Sensor on the Denso compressor from RA is Japanese, and even though the outputs read the same, swapping them out solved the problem. I'd give it a shot.
excellent, I'll be so happy once its fixed and I can quit worrying about it. I took a picture of my old compressor, I'm thinking you mean the one I have label 1. It seems like I could replace it without taking out the compressor, just lift the car. I would just have to go to a shop to have them drain the freon. But how much oil from the compress would drain out and could I just re add it from one of the above holes?
 

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I just replaced my compressor last week and changed that sensor with my old one because the aftermarket ones are junk plus, I knew the old one was working perfectly before. When u change that sensor if u have it clocked right you won't lose any oil. Make sure you hole facing up and you'll be fine. Oh and it is the sensor you labelled 1.
 

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Discussion Starter · #13 ·
I just replaced my compressor last week and changed that sensor with my old one because the aftermarket ones are junk plus, I knew the old one was working perfectly before. When u change that sensor if u have it clocked right you won't lose any oil. Make sure you hole facing up and you'll be fine. Oh and it is the sensor you labelled 1.
To have it clocked right, I would have to remove it right. When installed that sensor is on the bottom.
 

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Yeah I had mine off already so it made it easier. On the car it's a little bit of a pain in the ass due to the wires and harness bracket. If you was to take it off while its still on the car you won't lose too much oil if your quick and have the old one ready to go once you popped the junk one out.
 

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Discussion Starter · #15 ·
I switched out that sensor about two weeks ago and its been working fine. Thanks for all of your help everyone. This is a really helpful forum.
 

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Old dead thread 2014. That member has not posted sense 2014. If you look at their profile info. I would start your own thread. Detailing the problem. How it started and what you have tried.
I'd greatly appreciate it. I just don't want to order the wrong part or keep adding things to parts that are not the problem.

Thanks.
 
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