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Discussion Starter #1
Car: 2012 Sonata GLS 2.4L

Issue: When the car is at idle the air condition blow warm air. When driving down the road, air conditioner works ok

Troubleshooting steps taken: problem is the cooling fan does not turn on when the car is at idle. The condenser coil overheats because there is no air being drawn across the coil to cool it down - this trips the high pressure switch and turns off the compressor.
1. Replaced the cooling fan - no change
2. Tested the high speed and low speed fan relays - both good

This car had the engine replaced because the original engine failed (there was a recall for this), but issue predates the replacement of the engine.

Ideas, anyone?? Thanks
 

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There is no off/on compressor as it runs all the time albeit low output when not needed, but historically the electronic control valve at the back of the compressor needs to be replaced.
Some will want to replace the compressor to the tune of maybe $1000, rather than the control valve which can be had $20-$50 and then labor maybe $125. If you can do the job yourself, just the part, but the system needs to be discharged, evacuated then charged 19.3 oz R-134.
 

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Car: 2012 Sonata GLS 2.4L

Issue: When the car is at idle the air condition blow warm air. When driving down the road, air conditioner works ok

Troubleshooting steps taken: problem is the cooling fan does not turn on when the car is at idle. The condenser coil overheats because there is no air being drawn across the coil to cool it down - this trips the high pressure switch and turns off the compressor.
1. Replaced the cooling fan - no change
2. Tested the high speed and low speed fan relays - both good

This car had the engine replaced because the original engine failed (there was a recall for this), but issue predates the replacement of the engine.

Ideas, anyone?? Thanks
When you say you tested the relays, did you test the actual relay or did you remove the relay and bridge the contacts in the relay socket. If the fans fail to run with the contacts [in the relay socket] bridged or jumped, then you know the fault is after the relay socket towards the fan. If the fans fun with the relay socket bridged then the relays are not getting the required signal to close or the relays are faulty.

Check the plug at the fan. Is it getting power? Ground?

Turbonut seems to think the fault may be related to the compressor itself. You could try parking the car with large fan blowing into the grill. If the AC continues to work then I would say it's fan related and not a compressor problem.
 

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Discussion Starter #4
I pulled the relays out, set a meter to check for continuity (beeps when connected), and applied voltage to the 2 contacts that close the relay - meter beeped, so relays are good. Got a gut feeling I'm chasing something electrical, just not sure what. I had suspected the fan resistor at one point, but I have no idea how to test it
 

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Just because the relay switch is clicking doesn't mean the power is being delivered to the device. Need to check the other side. Contacts get bad.
I'd like to see what the pressures are doing and look at scan data.
 

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Either low freon pressure or high evaporator temp will shut down the compressor. If you speed up the engine when sitting still does the air become colder? Or if you put a strong fan blowing on the front of the car does the air get colder?
 

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^ Just remember, there is no clutch on this compressor (VDC) and the job of the control valve is to move the plate and create more displacement, more refrigerant, more cooling. If the valve isn't working correctly no a/c at idle, and some even find that when the valve is not functioning properly, when car is first started, the cold air can be delayed sometime 10-30 minutes, then runs fine until next time.
May be way off my diagnosis, but here's some info:

I've replaced 3 control valves, on 3 different vehicles and on my 2.0T replaced the compressor and all's been fine since, and all had the similar problem, delay start and/or no a/c at idle. Reason I replaced the entire compressor on my car was that with the high mileage (115,000) the compressor was noisey, so picked up a used unit with 23,000 for $55.
 

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2019 Sonata Sport 2.4L GDI
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My previous car, which was a 2015 Sonata Sport 2.0T Ultimate had the exact same problem. I took it in to the dealer twice for this. On the first visit they evacuated the system then added refrigerant and dye, which definitely helped but did not solve the problem. On the second visit they just scratched their heads and said everything was fine. At this point I was deep into my lease so I did not pursue it any further. My 2019 Sonata Sport does not have this problem.
 
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