A/C compressor clutch not engaging

MATIC1982

MEMBER
2014 KIA SPORTAGE
100,000 MILES

Hello,

I have a problem with A/C compressor clutch not engaging. A/C button turns on normally when you push it but the compressor does not engage.

I did some measuring and discovered that A/C clutch relay under the bonnet does not turn on. I've checked the relay itself and it does work. I discovered that one of the relay coil contact is constant 12V and the other, which should be GND to engage the relay, is 3V all the time, no matter of the A/C button state. So I assume something is wrong with the circuitry that controls the A/C relay. Probably bad transistor or something.

Do you perhaps have a wiring diagram for this? I would like to know where this relay wire is connected to, to which control module.

I am an electrical engineer so my goal is to repair it myself. The car is Kia Ceed 2014.

Your help is much appreciated.

Thank you!
Best regards,
Matic

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

The Kia Ceed isn't offered in the US, so I can't get schematics specific to it. However, I believe the Kia Forte is the same vehicle.

I attached the HVAC wiring schematic for that vehicle below. I had to cut the pics in half to make them readable, but I did overlap them so you can follow them.

Here are a couple of links you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

I hope this helps. Let me know if you have other questions.

Take care,

Joe

See pics below.

Images (Click to make bigger)