[MK75]

Hello,
I have a problem with the AC on my kia ceed cd (MY 2019) 1.6 CRDI 115 .
The AC starts and stops randomly, and some times it keeps turning ON/OFF for few minutes before getting back to 22 and Auto even it was not before.
Something else I noticed is that the AC and the outdoor temp sensor start and stop working at the same time ( I get --- for the ambiant temperature when the ac starts turning on and off).
I checked the ambiant temperature sensor and replaced it with an OEM brand new one and I still have the same issue.
Can anyone one please help me finding the issue.
Thanks Alot for the help.

 

[dubber09]

Hi, you need to check AC relay for function and AC clutch for wear as well as AC coolant for pressure/volume.

 

[MK75]

Hello,
Thanks guys for the support and for your answers, sorry for the late response.
I did charge the ac this summer so I don't think it's related to gas/coolant.
I think it's more of electrical problem.
It happens randomly.
When it works, it does function normally, but sometimes as if it did reset, it gets back to 22 degrees Celsius, ac and auto on, even though they were not.
I tried replacing exterior temp, I bought a used control unit that has the exact same reference, but I still have the same problem.
May a relay cause this ?
I checked the fuses and they are all good.

 

[dubber09]

Blown fuse would stop it from working at all.
Relays are in the fuse box under the hood.

 

[MK75]

Yup, but with a bad relay it won't start also, or at least the compressor won't engage

 

[ron1004]

Hello,
Thanks guys for the support and for your answers, sorry for the late response.
I did charge the ac this summer so I don't think it's related to gas/coolant.
I think it's more of electrical problem.
It happens randomly.
When it works, it does function normally, but sometimes as if it did reset, it gets back to 22 degrees Celsius, ac and auto on, even though they were not.
I tried replacing exterior temp, I bought a used control unit that has the exact same reference, but I still have the same problem.
May a relay cause this ?
I checked the fuses and they are all good.

If the gas charge is just a little too high or too low, a change in ambient temperature could activate the AC's pressure switch and lock it out.

The only real way is to have an expert AC shop hook up their instruments and diagnose it.

 

[dubber09]

What Ron said!
Also, if you overcharged AC system you may hear sudden and loud 'whistling' noise when driving - AC purge valve will relieve extra pressure in the system. It sounds like if a tire is losing air.

 

[MK75]

Except I don't have any of that, it works really fine, I have just that bug when it starts and stops, no weird noises, no wisteling, I barely notice when compressor starts if it was not the lights on the control unit. I have charged the gas at specialized garage where they mesured the existing amount and needed gas according to kia specifications, However I had the problem before that, except it was not as frequent as now.

 

[MK75]

Well, If someone get the same issue, I finally found out why, it was the defogging sensor, I spent money on buying control unit and exterior temperature sensor but I finally found it.
An easier way that I've learned to diagnose AC problems in KIA, is to keep pressing off button and 4 times the front vent button, it will run an automatic check and it will show a code, 00 if everything is okay and other codes depends on the model / MY they have different significations.