Cavalier AC blows cold while accelerating but is warm when Idle

[Lifnprogres]

Hi all,

I have a 2005 Cavalier Base 2D. Recently it has stopped blowing cold air when idle. When accelerating it blows cold just fine. I believe the problem is that the Radiator Fan does not turn on when I turn the AC on. I know the Rad Fan works because it turns on when the engine heats up just like it should. I have checked the fuses/relays. The AC system is holding R134 with no leaks. After doing some research it seems that the Rad Fan Motors fail fairly often but I don't know if it would be worth replacing because it does come on at about 220 F. Any help would be appreciated at this point because I live in FL and the dreaded summer approaches.

Thanks,
Justin

[Tech II]

Ok, you get cold air when driving down the road, but it gets warmer when you come to a stop?

So, if you lift the hood, start the car, and then turn the A/C on, the A/C clutch engages, and the compressor runs.....but the cooling fan never runs? But it runs if the engine temp reaches 220F?

Well, that tells me there is nothing wrong with the cooling fan or the circuit to it......I think your A/C system uses a pressure sensor to control the cooling fan.....it's possible this sensor is not providing the correct data to the PCM, which in turn would turn the cooling fan on.....on some systems, the fans run constantly....on others, it only runs when the pressure in the system reaches a certain point(in other words, the fan will cycle).....only way to check this sensor is with a Tech II scan tool.....in fact, a code for this may be set, but it may not turn on the CE light.....

[Lifnprogres]

Thanks,

I'm going to run it down to PepBoys (they have a free a/c check) hoping they mean with a tool and not their eyes

[jdsmith27]

Any update on this? I have an 02 cavalier doing the same thing.

[Lifnprogres]

Originally Posted by jdsmith27

Any update on this? I have an 02 cavalier doing the same thing.

Ok here is the solution! Replace the Radiator Fan Motor! It cost me about 25.00 bucks at the local autozone. They have them in stock. The problem is that there is a sensor that tells the car to turn on the fan while the car is idling. So that air is still being drawn through the radiator and it cools the freon for the a/c to work. So I spent about a week looking for this darn sensor. Finally a mechanic tells me that the sensor is "built in" to the radiator fan motor! I replaced it myself for about 30 bucks and it has worked perfectly for months now. Watch the youtube video and make sure that if you want to do it yourself you remove the top mounting bolts on the radiator so that you can "push" it forward to get the fan motor out. It will not come out unless you do this ( I tried to skip that step and found out the hard way.

Here is a link to the part ( I think you get $$ off when ordering online)

http://www.autozone.com/autozone/par...29805_0_0_6774

GL friend!

[gmtech1]

FYI, as Tech II stated eariler, the fan uses a signal from the PCM. The PCM reads high side pressures from a pressure sensor, the sensor is installed in the high side pressure line. There is no sensor in the fan motor. The motor itself failed on your vehicle, not the sensor. Glad to hear it's fixed!

[Lifnprogres]

Originally Posted by gmtech1

FYI, as Tech II stated eariler, the fan uses a signal from the PCM. The PCM reads high side pressures from a pressure sensor, the sensor is installed in the high side pressure line. There is no sensor in the fan motor. The motor itself failed on your vehicle, not the sensor. Glad to hear it's fixed!

Hi,

Your response is somewhat inaccurate. The fan motor did not completely fail as I have said it still turned on and ran when the car temp reached high enough. As I am an aircraft mechanic I am unsure as to why this is however if the fan motor had failed and not some type / form of sensor it would simply quit working. Instead it only quit working when the car was at idle and not yet reached 200 degrees. I'm not sure like I said as to why. But I checked this several times from cold start to appropriate temp. The fan would turn on when the car began to overheat as it is suppose to. It just would not turn on when the A/C was turned on before then. Either way replacing the fan motor fixed the issue, so I have to assume that the "sensor" or switch which tells the fan that the A/C is on is actually what went bad in my vehicle. And that item was part of the fan motor.

[Tech II]

I agree with Gmtech1....there is no sensor in the fan, that tech is wrong......even you said, the fan worked when the engine temp was too high.....coolant fans are controlled by the PCM....they are commanded on when when engine temp is too high, and when A/C pressure reaches a certain level......not sure if you had a bad connection at the motor....

[Lifnprogres]

Originally Posted by Tech II

I agree with Gmtech1....there is no sensor in the fan, that tech is wrong......even you said, the fan worked when the engine temp was too high.....coolant fans are controlled by the PCM....they are commanded on when when engine temp is too high, and when A/C pressure reaches a certain level......not sure if you had a bad connection at the motor....

I did check the motor as well as the connection, and I replaced the fan myself. Like I stated I don't know about a sensor in the motor however I do know that replacing the fan motor DID fix my problem and the old fan motor DID work fine. So far this is the ONLY place online that provided an answer to my exact problem which is stated above. Under the tech explanations I should have replaced something else to fix the problem. But I didn't, so logically whatever was wrong was located / a part of the fan motor.

If you guys want to further confuse the issue by stating it should have been something else (which it clearly was not) than you will only serve to confuse the people who come here looking for actual help. Bottom line is that it does not matter what the problem was. Only the that everyone knows the solution. If you have the EXACT problem that the post is titled with simply change out the radiator fan motor and the problem will be fixed. In the military we call that K.I.S.S. (Keep It Simple Stupid) I hope everyone can appreciate that I am not trying to argue with any "auto tech" guys just get a working solution to a problem that no one else but me had answered until now. If someone has this problem and replacing the radiator fan motor does not work than at that time I'd be happy to entertain the "troubleshooters" with further ideas. But the results speak for themselves IMO.

Thanks for everyone who contacted me with solutions

[gmtech1]

Hey, maybe I shouldn't have said anything. I was not trying to argue with you. I just wanted to let you know that there is no such sensor in the fan motor, that's all. Anyway, like you said, the problem is fixed and you have A/C again!

No offense taken on my end.

[Tech II]

Once again, I agree with Gmtech1.......and I'm getting sick of doing it!

Hey, if the solution worked for you, that's fine....we basically were agreeing that, that tech was wrong in stating that there was a sensor in the fan.....

I said that maybe there was a connection problem at the fan, but the other possibility was, the motor could have had a dead spot, and would occasionally not run when commanded on.....that's the only idea I can come up with, if the new fan runs ok now.......just glad you fixed the problem.....

[jakegday]

When you put your new radiator fan motor in, didnt you noticed theres ONLY 2 wires going to it?? a power, and a ground. No signal wire of any kind for any sensor. There is absolutely no sensor of any kind inside of your radiator fan motor.

[Georgia Sam]

I'm with you Lifnprogres. I have a 2004 Cavalier that had the same problem - a/c blew warm when idling - cooled car when driving. I noticed the radiator cooling fan wasn't running when the a/c was switched on. (The fan is designed to always run when a/c is on). So I took your advice and bought a new radiator fan motor for $25 at O'Reillys. The new fan started running immediately upon turning on the a/c. I now have plenty of cold air when idling. Problem solved. Thanks for the advice, Lifnprogres.