My AC has been acting up lately and I decided to try and diagnose it starting with the elecrical side.

Before you jump into a big electrical rabbit hole, have the system regassed. The electrical parts wont function if the gas pressure is out of spec.

Am I just thick

Well, there is an 'A/CON' relay. I wonder what that might be for 😀

 

Before you jump into a big electrical rabbit hole, have the system regassed. The electrical parts wont function if the gas pressure is out of spec.


Well, there is an 'A/CON' relay. I wonder what that might be for 😀

PCM controls A/C on / off via control head input to PCM, pressure switch to PCM as seen in engine data stream, along with PCM command "ON" for A/C

 

Chasing electric be waste of time if system not have at least 80 PSI to tell PCM it ok to fire up compressor

 

...For the life of me I cannot figure out which relay is for the AC in the engine bay box.

AC control relay (A/CON) and fuse -

 

AC control relay (A/CON) and fuse -

That's an A/CON fuse. But it's not the one that is on the wiring diagram you posted. The diagram shows the relay and the fuse are both on the engine bay fusebox. The image is a little fuzzy, but I think the relay fuse will be this one...

 

but I think the relay fuse will be this one...

Good catch!

 

Hi, hope someone can help me with my 2015 hyundai accent motion, I am have the same problem with the aircon not cooling or not working, so from all the chats I pick up a couple things that we can try, problem 1 if the PSI is lower than 80 how can I refill it if my aircon pump not coming on, 2 on the 2015 there is no relay in the Engine fues box, I have replace the A/C thermal sensor, test the coil on the pump all good, so I really need to know where the relay is for the Aircon and if it doesn't have one wat is the e electrical lay out. Please

 

2 on the 2015 there is no relay in the Engine fues box

According to the info posted earlier in this thread, there should be an A/CON relay on the engine fusebox. If your fusebox doesn't have one maybe that is why your A/C isn't working.

 

A/C been working fine for past 9 years, and the relay is not in the engine fuse box

 

A lot of the new stuff uses system pressure to PCM, a/c switch to PCM, and PCM commands a/c operation.

I use GDS and plug in before ever running shop looking for a/c machine to hook up gauge set, Have this info from driver in less than 2 minute, provide tablet plays nice connecting with car

 

Second question, if the pressure is around 80 psi it means the pressure switch will switch on the aircon pump, so how am I going to fill the unit with out the pump not come on 🤷

 

Sorry a mean if the pressure is around 80 psi the aircon pump will not work, because of the pressures switch, so wat do need to do to fill up the system with the pump not coming on

 

so wat do need to do to fill up the system with the pump not coming on

The gas is supplied in a pressurised container. So the pump (compressor) doesn't need to come on to fill the system. The pressure in the container should be able to push enough gas into the system to get the compressor working. At least that is how it works when your using a professional AC service tool to charge a system. I'm not sure how much pressure one of those DIY aerosol cans would be able to push in. But if the system isn't completely empty I would think a DIY aerosol would work. That is what they are for after all.

 

So what ended up being issue. Have same issue Hyundai accent 2014. Has no ac relay in fuse box. Checked and No power at compressor when engaged. Has gas and fuse good. Is the ac relay built into ecu ? Or is it built into bcm ? Or does it have its own ac module ? I’m suspecting it’s a relay issue as rest of ac system seems ok. Can anyone provide info on where relay is on these

 

Is the ac relay built into ecu ? Or is it built into bcm ? Or does it have its own ac module ?

I'm guessing your car, and the car belonging to the previous chap from South Africa, are both fitted with a variable displacement A/C compressor. That type of compressor doesn't need a relay because they don't have an electromagnetic clutch to control the compressor drive.

 

This likely what you looking for

 

Thanks mate. Nah not looking for that. As mentioned run tests and everything is good but no power to compressor. I’m certain it’s due to ac relay but the relay isn’t in fuse box. Just need to know what operates the relay. Is it the ecu ? Or bcm?

 

Would you have ac wiring diagram at all

 

What switches the ac on and off then. Where does the pressure sensor send info to for compressor to cycle on and off ?

 

What switches the ac on and off then.

The compressor you mean?
Variable displacement compressors don't switch on & off. The output of the compressor is continuously controlled via a PWM control signal.

Where does the pressure sensor send info to for compressor to cycle on and off ?

"I think" on this type of system the pressure signal is sent to the AC control module. And the control module sends the PWM control signal to the compressor.

 

Thank you. Yes just trying to figure out if there is a ac control module in this car ? Or if it built into ecu

 

Providing your RB Accent is wired same as my USA/ ETM, a/c pressure is fed to PCM.

A/C control module operates the ECV on the compressor

Ideally, you should be able to diag this thing in less than 30 minutes using GDS as seen in post #12, and using the SST called in the TSB I posted for you

DON'T make a complicated mess out of this, we not really have concerns beyond system being low from, or the random ECV on the compressor, to which with age, we just replace the compressor and have warranty on the compressor as new or Reman part