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2015 kia optima EX-L
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Discussion Starter · #1 ·
So have a issue with my Kia Optima 2015. When car is setting in drive way and it is normal temp.. say getting in the morning to go to work... When I turn on my AC wide open... I noticed my radiator fan does not turn on and it blows warm air while idle. When I back it out of the driveway and start driving it starts cooling.. I get out and check and the Fan is now turning like it should... I took it to Kia dealership.. and they told me the Fan is supposed to turn on as soon as the Air conditioner button is engaged... They said I had a bad Fan and wanted to charge me $732 to replace the Fan Assembly and control module. I found it hard to believe it was the fan..and I know how easy it is to replace fan assembly. So I bought new Fan Assembly and module myself for under $200 and it didnt take 15 minutes to put in... I am glad that I did it and saved myself $500 bucks.. However it still has same symptoms so the Dealer Ship was a pure rip off.. They Charged me $120 and swore it was a bad fan. So now I have a new Fan Assembly and module and still same problem.... Quesion is the Fan supposed to turn on as soon as the Air Conditioner button is engaged? And if so what else would cause it not to turn on but turns on once engine gets warmed up?
 

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2016 Kia Optima SXL Kenetic
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I just read your post and i had to try for myself.... My car blew warm air for about 1m:30sec -2m:30sec. then the cold air came. Are you saying you air conditioner doesn't work till your engine is warmed up?
 

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Discussion Starter · #3 ·
I just read your post and i had to try for myself.... My car blew warm air for about 1m:30sec -2m:30sec. then the cold air came. Are you saying you air conditioner doesn't work till your engine is warmed up?
That is correct, doesnt seem to get Cold until engine is warmed up.. So when I first get in car and crank it up with the engine cold for several hours , the radiator fan doesnt immediatly turn on. Then after Engine gets warmed up the Fan will kick on, then it will start to get cool but only after that then after I start driving. Very weird... Dealership says fan should turn on automatically when AC is turned on no matter what... but of course they told me I had a bad fan and I bought a brand new Fan and control assembly and still same problem... I will be interested if you would try to let your car cool deal all the way then pop the hood.. Crank it and turn on the AC and see if your fan comes on immediatly or if it takes several minutes for it to kick in.
 

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2016 Kia Optima SXL Kenetic
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With A/C systems, it is important to know in what order things turn on and off. From your description, it sounds as though the compressor clutch is only engaging for a short period of time. This is usually due to a low refrigerant level. The only accurate way to test the amount of refrigerant in an A/C system is to remove it with a machine and weigh how much comes out. Many people confuse pressure in the system for the system being full. Volume and pressure are two different properties of a gas, which the refrigerant in your A/C system is a gas when it is allowed to escape to the atmosphere.
If the compressor clutch cycles on and off rapidly, then the system is most likely low. The best remedy for this is getting your A/C serviced.
From you description, it sounds as though the system isn’t building enough pressure, and by relation enough heat to turn the cooling fans on. In other words, the system is low on refrigerant. I would confirm this by connecting A/C gauges to the system to see what the pressures are on the high and low side of the system. If the low side sucks into a vacuum quickly, I would suspect a low system. If the high side spikes and the fans don’t turn on, I would suspect a problem with what is called the A/C pressure transducer (high side switch), one or both fan relays, the fan motors themselves, an ambient temperature switch or the sun sensor.
If the compressor is running long enough to build heat in the high side of the system, and the cooling fans don’t turn on, I would begin finding the fan relays and add power to the appropriate circuit to see if the fans turn on at all. This will require a wiring diagram. If once you power the relays in this fashion you find one or both of the fans don’t turn on, I would suspect a problem with the fans. If both fans operate then it is time to take a look at the pressure transducer. Don’t let this strange name fool you, it is simply a sensor that relays the amount of pressure in the system to the PCM and the PCM decides when to turn on the fans and or compressor clutch. Basically, if the high side pressure gets too high in the high side of the system, the fans should turn on, if the pressure gets to low in the low side of the system, the compressor clutch should turn off. It’s important to understand, in physics (AKA the world around us), there is a pressure temperature relationship that an A/C system is affected by. The higher the pressure the higher the temperature, the lower the pressure the lower the temperature. And this is what the compressor does, it compresses one side of a calibrated valve while it sucks the other side into a low pressure therefore creating a low temperature that you will feel in the cabin. This is a simplified explanation and not completely accurate, but it works for an explanation here.
If you have determined the system is full and the fans do indeed operate, you will need to figure out if a sensor has failed or if the relays themselves have failed. There are two relays on your car. A high speed and a low speed. I would swap these relays and see if anything changes. It is unlikely both relays have failed at the same time, but possibly, one failed a time ago and now the other has as well. If you feel this is a possibility, buy two new ones and replace them. Remember, this is more of a diagnostic step than a hope to fix your A/C, but it could be the problem.
There are three potential sensors that could be a problem. The ambient temperature sensor and the sun sensor are not common failures. The transducer is another story. This part can get really complicated, but the first thing to do is run the A/C with gauges connected to observe the system pressures and monitor the circuit from the PCM to the relays. You are looking to see if the PCM sends power to one or both relays to turn on the coolant fans. This should happen as the high side of the system approaches 214 psi. If it exceeds this amount of pressure and the system doesn’t turn on, one of the sensors in the system that the PCM uses to know when to turn the system on and off has failed.
If you have made it this far, I applaud you. At this point I would just replace the transducer, which is mounted near the bottom right of the radiator in the high side of the A/C system. They are not to expensive and a common failure. Testing of the high side switch, which is what they are better known as, is problematic. The ambient temperature switch and the sun temperature switch are as well. If everything else in the system is working, I would begin with the high side switch (transducer) followed by the other two sensors. They are much less common failures therefore are harder to find.
Good luck. I hope you have a successful diagnosis of your A/C system. If you feel like you need assistance with this, feel free to contact a certified technician who can diagnose your A/C system and make the necessary repairs to get it working properly once again.
 

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^Too long to read. but incorrect information. These cars use a VDC and they DO NOT have a clutch.

Normally, if the cold air is fine, meaning extremely cold once operating, but a delay in starting, sometime 5-10 minutes, the electronic control valve in the back of the compressor is kaput. The fan will run whenever the A/C is on, but the high speed fan will cycle on/off depending on head pressure.
The high side pressure transducer will send info, convert pressure to voltage, to the ECU and will activate the fan when needed. Normal value 4.5v.
 

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2015 kia optima EX-L
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Discussion Starter · #6 ·
Correct the compressor is a VDC does not have a clutch. Ok so more info I gathered this morning.. Couldnt take it to the shop as its the 4th of July and last time dealer ship ripped me off saying I had a bad fan which I replaced with control module and still same thing... I am not taking it back to that dealership. However here is the deeper breakdown of the scenario

So car engine is cold setting in Garage.
1. Crank the engine and turn on AC full blast.
2 radiator fan does not turn on until about 2 minutes after cranked.. Stays on for about 2 minutes then cuts off.. Stays off another 2 minutes then kicks back on.... goes on and off...
3. Air is just blowing warm air.
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4.. I back the car at and drive around the subdivision. Cold air immediatly starts blowing.
5. Park the car and let it run for 20 minutes, fan continues to run never turns off and continues to blow cold air fine.
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So it seems it is only doing this when car is started cold and the air conditioning is on... Just blows warm air and of course the hotter the inside of the car the hotter it is until you actually get the car on the road.

So the fan works... I would think that also means the relay is working???.... So is it some sensor that is only doing this when car is cranked up when the engine is cold???

Thanks in Advance for everybody's help.
 

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Just came back from shopping, and must state that the low speed fan operates when a/c is on, or is supposed to, but the high speed fan is governed by the transducer. I've got to do some digging but also believe the fan is coupled to the compressor, being that the swash plate isn't moving, no demsnd from the valve, no air,, no fan.
 

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Discussion Starter · #8 ·
Just came back from shopping, and must state that the low speed fan operates when a/c is on, or is supposed to, but the high speed fan is governed by the transducer. I've got to do some digging but also believe the fan is coupled to the compressor, being that the swash plate isn't moving, no demsnd from the valve, no air,, no fan.
Thanks being trying to find a schematic for the 2015 optima AC to try to help troubleshoot but cant find anything on the web.
 

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I still say it's the control valve. Exact symptoms, no air at start. When mine A/C went out over 3 years ago there wasn't much discussion about the valve, but when I tested the evap temp sensor, high side traducer, fan, valve for voltage, pressurs @ 105psi when off, all checked out fine, replaced the compressor {see below) good to go.

Posted this before, but the '11 2.0T would be sporadic, at first start, a couple of minutes to start cooling, but then cooling took longer and longer, maybe up until 15 minutes before starting to cool. One day when it was about 95, cooling started about the same, maybe 3 minutes then worked great, ice cold, stopped for lunch, immediate cold air, stopped to do some shopping, cold air fine, then stopped at Walmart, but when the car was started, no air on the 20 minute drive home, no cold air at all. Wife gave me an ultimatum, fix the air or use her car, so the next day installed a used compressor with 23,000 miles ($60). Reason I went used, and not just the valve, was that the compressor was noisy, and after the install, 3 1/2 years later air fine.

I've had this on file:

Keep us posted.
 

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Discussion Starter · #10 ·
I still say it's the control valve. Exact symptoms, no air at start. When mine A/C went out over 3 years ago there wasn't much discussion about the valve, but when I tested the evap temp sensor, high side traducer, fan, valve for voltage, pressurs @ 105psi when off, all checked out fine, replaced the compressor {see below) good to go.

Posted this before, but the '11 2.0T would be sporadic, at first start, a couple of minutes to start cooling, but then cooling took longer and longer, maybe up until 15 minutes before starting to cool. One day when it was about 95, cooling started about the same, maybe 3 minutes then worked great, ice cold, stopped for lunch, immediate cold air, stopped to do some shopping, cold air fine, then stopped at Walmart, but when the car was started, no air on the 20 minute drive home, no cold air at all. Wife gave me an ultimatum, fix the air or use her car, so the next day installed a used compressor with 23,000 miles ($60). Reason I went used, and not just the valve, was that the compressor was noisy, and after the install, 3 1/2 years later air fine.

I've had this on file:

Keep us posted.

Thanks.. Can the control valve be replaced without having to have the refrigerant evacuated first?
 

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Sorry to say, no. Discharge, change valve, evacuate maybe 45/60 minutes, charge 19.3 oz, I believe.
Said this before, the problem with the VDC is that the innards are turning all the time, even when the A/C is off so that oil is recirculted to lube the compressor. This presents a problem as with the clutch type system, the car could be taken to a shop, discarged, driven home, repairs made, back to shop the have evacuated/charged, not with this compressor. If this compressor is run w/o a charge, no oil circulation, compressor freezes, pin shears on the hub assembly so that the car can still be driven though.
 

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So have a issue with my Kia Optima 2015. When car is setting in drive way and it is normal temp.. say getting in the morning to go to work... When I turn on my AC wide open... I noticed my radiator fan does not turn on and it blows warm air while idle. When I back it out of the driveway and start driving it starts cooling.. I get out and check and the Fan is now turning like it should... I took it to Kia dealership.. and they told me the Fan is supposed to turn on as soon as the Air conditioner button is engaged... They said I had a bad Fan and wanted to charge me $732 to replace the Fan Assembly and control module. I found it hard to believe it was the fan..and I know how easy it is to replace fan assembly. So I bought new Fan Assembly and module myself for under $200 and it didnt take 15 minutes to put in... I am glad that I did it and saved myself $500 bucks.. However it still has same symptoms so the Dealer Ship was a pure rip off.. They Charged me $120 and swore it was a bad fan. So now I have a new Fan Assembly and module and still same problem.... Quesion is the Fan supposed to turn on as soon as the Air Conditioner button is engaged? And if so what else would cause it not to turn on but turns on once engine gets warmed up?
I'm having this exact same issue on my 2015 Kia Optima. Was this resolved with the last posters recommendations?
 

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I'm having this exact same issue on my 2015 Kia Optima. Was this resolved with the last posters recommendations?
If static pressure @ 100, ice cold air when driving, but delay at start and low speeds, change control valve or compressor.
 
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