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2012 KIA Sorento
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Discussion Starter · #1 · (Edited by Moderator)
Hello everyone,

I have 2012 Kia Sorent FWD with 3rd row and rear AC. I have strange issue related to my front AC. Main issues:

Symptoms:
  1. Engine fan does not switch to highest speed to cool car when is not moving.
  2. AC is working because when I am driving I am able to cool off whole car.
  3. Coolant level are okay.
  4. AC will turn of faster when i will enable rear AC.
  5. You can freeze inside car when car moving and both AC are working.

I have replaced AC resistor and ambient temperature sensor. Both were little off of the norm but not really too much.

Engine is not overheating because fan is working at low speed but will not go to highest speed. Yet fan can work on highest, because I have connected fan directly to the battery and was working like crazy. .
Relay seems to be okay. I switch them around in places and all is working.
AC self-diagnostics shows no errors "00"
Fuses are okay.

I am stun... not sure what is wrong but i guess it is some kind of sensing element, sensor, relay or something which will not kick in fan to highest speed.

Thank you for all your help!
 

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Sorento 2012
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Study the linked page: Kia Sorento: Cooling Fan Description - Cooling System - Engine Mechanical System - Kia Sorento XM 2011-2021 Service Manual and the pages before and after the linked page.

The fan speed is controlled by the ECM, which is looking at A/C switch position, A/C pressure or load, vehicle speed, and engine coolant temp. The pulse width modulation (PWM) is sent to the fan motor by the Cooling Fan Control Module. You will need a scope to read the wave forum and frequency. Also notice that the motor never gets 100% and tops out at 90% power.
 

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2012 KIA Sorento
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Discussion Starter · #3 ·
Study the linked page: Kia Sorento: Cooling Fan Description - Cooling System - Engine Mechanical System - Kia Sorento XM 2011-2021 Service Manual and the pages before and after the linked page.

The fan speed is controlled by the ECM, which is looking at A/C switch position, A/C pressure or load, vehicle speed, and engine coolant temp. The pulse width modulation (PWM) is sent to the fan motor by the Cooling Fan Control Module. You will need a scope to read the wave forum and frequency. Also notice that the motor never gets 100% and tops out at 90% power.
Jolt2,

Thank you for your respond. I have oscilloscope (old for electronic staff repair) and I will try to check Hz sent to/from the ECM. Once question.. does cooling fan control module is the resistor that controls fan or this is an electronic module in line with other components. It does not say clearly of what it is.
 

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2012 KIA Sorento
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Discussion Starter · #4 ·
Jolt2,

Thank you for your respond. I have oscilloscope (old for electronic staff repair) and I will try to check Hz sent to/from the ECM. Once question.. does cooling fan control module is the resistor that controls fan or this is an electronic module in line with other components. It does not say clearly of what it is.
I think this page answers my own question Cooling Fan Control Module .
 

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White 2012 SX AWD
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Note that the ksmanual pages show "2011-2021" and I'm not sure that it's possible for the information to be the same for all of those years / models. Some information may not apply to our 2011-2013 XM models.
 

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I will post this as I have said before:
"That free on-line info from KIA is more generic info for the Sorento. It is closer to covering a base 4 cylinder model of the Sorento so a lot of the pictures do not totally match. It is to be used as a reference. If you want info that matches your Sorento then you need to get a subscription to KIA Global Information System (KGIS). Also remember that service manuals are written for auto service professionals and will not cover every little detail. Do not waste your money on ALLDATADIY.com as they only copied the info from the free KIA site that you already have.

The link to KGIS is : Kia Global Information System (KGIS)"

You need to also look at the inputs, meaning the information that is coming into the ECM. Bad info in equals bad info out. It could be related to a poor engine temp sensor or a bad thermostat that could be affecting the fan operation, really any input used by the ECM to determine the fan output speed. It could even be a software issue in the ECM. Have all the updates been done to the ECM? In that case if KIA does know about the issue, they can not fix it.
 

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No worries...just wanted to make sure OP realized this.

Also, from what I remember, the fan on my 3.5 v6 I believe is not a variable speed fan. I think it just cycles on and off at specific temperatures.
 

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Discussion Starter · #8 ·
No worries...just wanted to make sure OP realized this.

Also, from what I remember, the fan on my 3.5 v6 I believe is not a variable speed fan. I think it just cycles on and off at specific temperatures.
Alright,

I have being working on this for some time and I got it resolved. The issue was that HVAC Pressure Transducer was leaking and also not measuring correctly voltage. I followed manual troubleshooting guide and remedy issue, replaced switch, I can freeze inside car now. I used a134 gas with UV leak solution. Was little tricky but I found it. Thank you all for your help!
 
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