Heating and Cooling the Cabin - The HVAC System

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Staff member
Jul 8, 2015
A thread for detailing the components and functioning of the HVAC system of the 2014-2019 Soul EV.
For the 2020 on onwards try Exclusive: details on Hyundai’s new battery thermal management design

Note : Before September 2020 there was no connection between this system and the battery fan. Any mention of Thermal Management on this page is unrelated to heating / cooling of the battery.

Image from - US Kia Promotional material filename - 'PS EV at PEVC March 2014 FINAL v2.pdf' - the link I had is now dead.

The entire climate system in the Soul EV is made by Hanon Systems- their page on the Cluster Ionizer is here - Hanon Systems : Thermal Management Solutions
(Apart from the PTC Positive Temp Coefficient Heater which is made by Daewoo, perhaps Hanon subcontracts this part.)
This company was formerly known as Halla Climate Control Corp who merged with Visteon in 2013 and both then became Hanon Systems. -- see Halla Visteon Changes Corporate Name to Hanon Systems

A June 2018 article about Hanon - 'Diversification key for Hanon Systems' success'


There is report about testing the HVAC system. - http://energy.gov/sites/prod/files/2015/07/f24/vss135_meyer_2015_o.pdf
It seems the heating/cooling system in the Soul EV was extensively tested, and we can see the results.
Winter testing Jan2014 International Falls, MN. Summer testing Jun2014 Death Valley, CA


From an earlier thread on this forum there is some data about the energy use of the heat pump in very cold weather.
see - Winter in Toronto

Also from this thread - Heat Pump vs No Heat Pump
The two versions of the MY2018 Soul EV sold In Korea are the Standard and Economy.
One of the differences is that the Economy version lacks the heat pump.
This causes a 15km reduction in range when the temperature is -7C.

A technical paper by Hanon - Range Extension Opportunities While Heating a Battery Electric Vehicle


Here's a diagram of the heat pump system. It is the compressor that pumps the refrigerant gas / liquid around the system.

From the service manual - here is the heat pump system layout.
see - Kia Soul EV (PS EV) 2015-2020 Service Manual / Heating,Ventilation, Air Conditioning / Heat Pump /


Note: In a heat pump system it is the compressor that pumps the refrigerant around the car. Sometime it is a gas and sometimes a liquid depending on temperature and pressure. The specific type is R134a (1,1,1,2-Tetrafluoroethane).
Occasionally I see references to R-1234yf (2,3,3,3-Tetrafluoropropene) but this seems to be mistaken.


Interesting. Now, my big question is if I have the cluster ionizer in my car. Do you see the "CLEAN MODE" and "ION MODE" described in the service manual in your info screen in any way, or any other way for that matter?

I tried the magic trick, holding the OFF button and pressing the "MODE" button fast several times. It actually worked, and the numbers 00 started flashing, which hopefully means it is installed.

Video ION Cluster test

I also opened the glove department, and removed the cover for the air inlet filter. But I didn't really know what to look for. Is it situated on the right- or left hand side? And is it even possible to spot without disassembling things?
I think the Cluster Ionizer is standard on all our cars. It just gets called 'Clean Air' in some places and 'Cluster Ionizer' in others.

There is a patent for this at Air purifier with cluster negative/positive ion generator


This is a Cluster Ionizer.

About the Cluster Ionizer - from page 977 of the service manual -
1. The function of cluster ionizer is cleaning air by sterilizing and dissolving of air conditioner.
2. The function of cluster ionizer is controlling mold caused by stench of air conditioner and external inflow of air.

The Cluster Ionizer makes a disinfection and decomposition of a bad smell from the air-conditioner or inflow air. And it cleans inside air of a vehicle.
When running an air-conditioner or heater, it starts with "CLEAN MODE" on it and repeats from "CLEAN MODE" to "ION MODE" and from "ION MODE" to "CLEAN MODE" every 15 minutes.
In the CLEAN MODE, the cluster ionizer generates negative ions and positive ions and makes a disinfection and decomposition of a bad smell from the air-conditioner or an inflow air. The cluster ionizer has functions as follows; a deodorization effect, a disinfection effect, and an air-cleaning effect.
It has an operation indicator lamp on the upper side of its display area and shows whether it is operaing or not.
In the ION MODE, the cluster ionizer generates negative ions and cleans inside air of a vehicle.It has an operation indicator lamp on the lower side of its display area and shows whether if is operating or not.

It seems the Cluster Ionizer is accessible from behind the glove box where you change the air con filter.
Cluster Ionizer Replacement
1. 	Disconnect the negative (-) battery terminal.
2. 	Remove the glove box housing. (Refer to Body -"Glove Box Housing")
3. 	Disconnect the cluster ionizer connector (A).
4. 	Remove the screws and then remove the cluster ionizer (B).

There's a post on the Quebec Soul EV Forum about a leaking HVAC system. This seems to be a very rare error.


For those who would be interested. I had an air conditioning problem with my soul ev 2015 (December). Apparently I'm the only one who has the problem right now. According to the dealer's diagnosis, I have leaks (see photos). They will replace the 3 way valve with the pipes... short pieces are in b / O, so it will probably take several weeks or pt months before the air conditioner is functional. They don't know what the problem is. Other kia soul ev may have the problem eventually. So I can share the adventure and some photos that show the problem identified by kia boisvert.

Another subsystem of cooling that does interconnect with the HVAC is the liquid cooling of the electrical components at the front of the car.
Again this is not related in any way to cooling of the battery, and it is not part of the heat pump. The liquid is pushed around the system by an EWP (Electric Water Pump).

Here's a schematic of where the EWP moves coolant around.

From the service manual - here is a schematic of the coolant reservoir.


Here's a picture with the OBC (On Board Charger) and the High Voltage Junction Box moved so you can see the coolant reservoir (the white plastic water tank) and water pump beneath.

The inlet for the coolant into the OBC (On Board Charger) looks like this. You can see the green liquid coming out.

This coolant is an ethylene glycol mix commonly called anti-freeze. I have the green variety in my car, but others have stated blue.


A thread that discusses the Electric Water Pump EWP is here. - Electric Water Pump


A new thread discussing problems with the heating / cooling system - Heat pump stopped working, no apparent cause


The entire HVAC system is managed by an ECU known as FATC (Full Auto Temperature Control).
It is connected on the CAN line to the rest of the car's systems.

The first update to the HVAC system firmware came in September 2020.

TECHNICAL SERVICE BULLETIN: SERVICE ACTION: BMS/FATC OPERATION LOGIC IMPROVEMENT WHILE BATTERY CHARGING (SA427) - This bulletin provides the procedure to upgrade the Battery Management System (BMS) and Full Auto Temperature Control (FATC) software on some 2016-2017MY Soul (PS EV) vehicles, produced from May 21, 2015 through August 29, 2017, in order to improve air conditioning operation while the battery is charging.

Hi all,

I have a 2016 Soul EV with heat pump. It's summer time now and I'm finding the cooling is weak. My garage verified the gas pressure is good. It was 25C outside with low humidity, we ran it on the highway 100Kph for 20 mins after being parked outside in the sun for a couple of hours. Setting to 17C (min) and AC and front dashboard vents, the driver side was pretty cold, but the passenger side was so-so. No amount of fiddling would help.

A time later had turned on the vehicle parked and ran the AC same settings, let it run for 10 mins. Seems from left to right each of the 4 vents gets a little warmer. The one to the left of the driver (near door) is best. I tried cycling thru the vent modes and everything worked correctly. I checked the cabin filter, it is ok. I used a laser thermometer to measure. It was about 15C at the middle left vents and 21C at the middle right vent. Weird. The thermometer is very sensitive and these were the lowest values I could get.

I then opened the hood to check the pipes. The hot pipe was very hot, almost burned my hand. The cold pipe was meh,, cool to the touch, not cold and def no condensation, very dry.

Just to compare, my old ICE 2011 CRV,... I start the vehicle, turn on the AC, and freezing cold air within 1 min. I did not check the temperatures at the vent, nor the pipes.

Cheers and thanks!
I have a 2018 with heat pump. It definitely takes a couple of minutes to produce cool air, but my system minimum temperature is 15. Is 17 a typo? Do you by any chance have the "driver only" button pressed?
Hi, I'm in Montreal, Quebec, Canada. The temp control goes as low as 17 Celsius (not a typo). I do have a driver only button, no impact on the min setting. Just trying to decide if I should go to the dealer (very expensive) and I do not like Kia Canada corporation (last resort).

I believe the driver only button inhibits heat and/or cooling to the front passenger vents, which might explain your symptoms if it were pressed, or the condition was set because of an electronic fault.

Have you tried disconnecting the 12V battery for a good long period (say overnight), to reboot all the systems after allowing capacitances in the electronics to discharge? That could fix the driver only setting if that's an issue.
Hi all,

I think we're getting off track (lol). The main issue is the coldness of the AC coming out of the vents. The garage verified the pressure of the gas, the hot pipe is extremely hot, the cold pipe is pretty much room temperature. Is this normal? Best temperature reading was about 15C from the center left vent using a laser temp gauge.

The fact that the air temperate from left to right vents gets warmer is an observation and the volume of air coming out of each is pretty much equal. I don't think its a stuck driver only vent actuator door issue. Maybe something else?

A hot pipe indicates that a lot of heat is being extracted from the air supply, so that's good. Ambient temp on the cool pipe indicates the refrigerant is being adequately cooled by the external heat exchanger. Cooling below ambient takes place in the evaporator inside the cabin. The pipe temperatures are similar to mine, and 15 degC sounds about right, compared to mine, but, of course it should be about the same at all outlets. There is only one internal heat exchanger, so something is preventing some of the air supply reaching it. My money is still on the air control actuator(s). Try the recirc control - it may unstick something.
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The hot pipe burning hot, the cold pipe ambient temp is considered correct. About 15C at the vents is the best we can get. Is this correct?

As far as temp differences at the 4 front vents, even though the CFM at the 4 vents is approx the same, you think there might be a stuck actuator? Note that the mode control (window, dash, feet, mix) works correctly and the driver only works correct.

I guess I'll start with the self diagnosis. (heater_amp_a_c_control_unit_fatc_repair_procedures-2923)
Kia Soul EV: Controller / Heater & A/C Control Unit (FATC) Repair procedures
Turn on car, hold OFF button and press MODE 4x and see what codes appear on the display.

Any other suggestions?

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I am a refrigeration mechanic, the temp of 15C output with 25C outside temp sounds about right. Have you tried cycling the outside/inside air switch? That is one of the air dampers, make sure it is working. You said you had the pressures checked to be correct.
Thinking about it a bit more. With the suction line being only slightly cool, It could be that the expansion vale is not working correctly. If it isn't opening up properly, it will limit flow of refrigerant causing uneven cooling through the evaporator coil. If you don't find anything else with failing dampers. Perhaps find a different A/C mechanic to have it checked, mention a possible faulty expansion valve, have it checked specifically for the correct superheat.
Also, I have some suspicion of your minimum temperature being 17 degC. I can't see why it would be different to mine. Could anyone else with a 2016 with heat pump comment on their minimum temperature, please?
My 2015 with heat pump goes down to 15C.
Here's a 2016 from Norway. Presumably also with heat pump.