A/C not working?

Yep, it sounds like the compressor is starting to go out which depicts the pressure you have, I would confirm the compressor is the problem by doing a CAN scan. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is one for about $99.00 if you need it:

https://amzn.to/3ZixY4v

This is to rule out the AC control module. 9 times out of ten it will be the compressor here is how to replace it in the images below.

This video will help you vacuum down and recharge the unit:

https://youtu.be/4EqdrBVb0sY

Here are the capacities as well, remember the new compressor will have the oil already inside of it so don't add more unless you lose some in the replacement. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.

Sounds good, with today's car a CAN scan will help tell us the system or direction to go in. I do not see the control valve you speak of, can you upload an image or give me the video link?

Hello, I just wanted to add a little info here. Thats a lot to diagnose the system. And I don't see why the shop is not able to look at some live data from the AC Control Module. Especially on a 2017. Things such as the Evaporator temperature sensor, ambient temperature sensor, etc. It might not be setting any codes in the A/C (HVAC) module, but the live data still has value. From your pressure readings, 58 is high for the Low-pressure side and the 135 is low for High pressure side at 72. This shows that possibly too much refrigerant is flowing into the evaporator. You do have a variable swash plate compressor. Do the pressures even out when the system is static (not running)? It's a big deal with A/C work, it can be tough to make a call on a compressor when so many other components are involved. I think the dealership means (manually) just pulling things apart and seeing what they find.

The A/C system does have a Pressure transducer which is not an On Off switch, it's an actual pressure sensor which there should also be a live data PID for in the PCM or HVAC control module. I'd be interested in seeing if you can pull up some of these live data PIDs just to see what they are reading and if any of it matches your gauge readings. I assume these pressure readings are with AC on max and the Recirc button is On and try 1,500 RPMs. Also see if there is an Evaporator temperature sensor data PID.

But looking through some service info, just on pressure readings alone, it points more to an Expansion valve (TXV) stuck semi open/closed, or the Temperature sensor is reading incorrectly. Granted this is just going by pressure readings,
Normal would be around 30 PSI on the Low and 200 to 250 psi around 70f. That would be normal at 1,500 RPMs. You might try having the system evacuated, pulled into a vacuum and refilled. Not sure how accurate this chart is for R134A refrigerant. High side looks a little low on the chart, for 70f. But see about the scan tool live data if possible.

I hope this info helps somewhat, it would be terrible to replace the compressor and not resolve the issue.

Well, changing out the expansion valve is going to be a bigger job, it sounds like you have someone that's giving good advice, so that's a plus. As for the scan tool I thought you already had one. A basic OBD2 scan tool will only scan the engine computer unless stated otherwise. To access the HVAC module, you'll need a scan tool capable of that. The Link below is for a scan tool that is Bluetooth to your phone and works with an App. It's actually a great scan tool for $120. It will do actual bidirectional controls, full system scans of every module in the vehicle and a ton of functional options. If you're planning on trying to fix your own vehicles in the future, this is the way to go. This scan tool does more than my $500.00 Autel. You should have no problem accessing the HVAC module with this. You will be able to get into the manufacturer side of the diagnostic system as well as the OBD2 Global data. It will probably pull up codes you didn't even know were stored in other modules.

https://www.amazon.com/Thinkdiag2-Bidirectional-Diagnostic-Bluetooth5-0-Intelligent/dp/B09YRDGY3Z/ref=sr_1_1?m=A2MGOU7GTZSI2X&marketplaceID=ATVPDKIKX0DER&qid=1675504175&s=merchant-items&sr=1-1&ufe=app_do:amzn1.fos.f5122f16-c3e8-4386-bf32-63e904010ad0

Hi Miami hot, sorry for the delay, this other post came up as spam due to our filters, I apologize for that. As for the Think Diag, did you run all the updates on it yet? I'm sure there are a bunch. Were you able to do a full system scan on the vehicle and see/or communicate with others? I will look up the HVAC control module info and get back to you asap.
Ok do you have Auto AC or Manual? Auto AC should be able to set a temperature in the vehicle and it should keep it there.
The vehicle does have an AC Control Module, so if you cannot communicate with it that might be the issue with the system, it might not even be turning on the compressor, or there might so other fault occurring. And yes, the Think Diag is a complicated scan tool, but all the advanced ones are. It's much better than just a global OBD2 code reader. You'll get the hang of it.
Just verify you can read live data from any other module, newer more advanced scan tools will have the option to enter the Global OBD2 standard side or the Manufacturer side where it should scan for your VIN, show the correct vehicle and allow to enter into specific modules. So as long as you can get into the ECM, BCM, etc and read codes, check live data. The scan tool is working, they do need updates, some of my scan tools with have updates for different vehicles every week or so. But if you run the updates and still cannot communicate with it, we should check that it is getting power and ground.
Does your Blower motor come on?
From Hyundai, the 1st diagram shows what to look for if a leak is suspect, oil and possible frost on a line connections. 2nd is the Pressure relief valve seal on the compressor, that it is still intact. I know we might be dealing with a different issue here, I just wanted to put these out. Hyundai is pretty good with their service information.

Here is the 2 HVAC controls 3rd diagram, the top is a Manual System, the bottom is the Auto AC system. Both have different wiring setups so we need to know which one we're chasing.

Okay, cool. nice work. It will show the HVAC (A/C control module) if it is communicating on the network. The fact that it is not can mean a few things. Either the module is down completely and not talking on the data network, the communications section of the module has failed, there is a break in the c-canbus network wiring (unlikely here), the module is not receiving a wake up signal (On/Start Input, On Input). I know this all sounds like a lot, but by checking some voltage readings at the hvac connector we can see what is missing, and try to get it back online if possible, or see if its something else effecting it. The data bus network in this vehicle is complicated. The 2 main networks we are concerned with are the "K-Line" and the "C-Canbus" networks. Even by 2017 things have advanced a lot.
So, the first thing I need you to do is scan the entire vehicle and write down any codes you find in any modules. Just to be sure there is no other module or input that doesn't look right.

Are you comfortable using a basic multimeter to check some voltage readings? It will only be 12volts DC or less. No biggie. There are a couple Joint Junction connectors that the C-canbus network wires run through and out to other modules, canbus is a 2 wire twisted pair, so I will try to find these junction blocks first.
I missed if the Blower Motor was working or not? I see the LEDs are working on the hvac module, but can you change speeds of the blower motor, or vents from Floor to Dash?

This 1st and 2nd diagrams are the wiring harness running through the Dash, to the left "View A" is where the JMB Joint Connector is, it's a white 8 pin connector. Diagram 4 shows pin 6 (blue wire) and pin 3(Red wire), they are the 2 wires (c-can bus) coming from the AC Control module. With the key Off. Check that this connector is not loose or corroded. We will start there since the AC module seems to be powered up, just no comms. We will take some voltage readings of the back of the A/C Control module itself if needed.
Also check the fuses in the 5th diagram. Let me know what you find. If communication comes back, then we know there is a pin fitment issue near that lower driver side dash area.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Okay, cool. Really, we just need to make sure the JMB connector with all the red and blue wires running into and though it is okay. If there's an actual wiring issue with the c-can and that module is the only one not talking, the wiring problem has to be either in that connector or at the back of the A/C Control module. It might be tough to find because I think it's on the back side of that (View A) fuse panel. This is the OEM (manufacturer) diagram and there are Can bus wires so you should be able to communicate with it. But I have seen where a module is powered up, but the communications section of it was not able to talk to a scan tool. Have you tried using the generic OBD2 scan with the ThinkDiag, instead of the manufacturer side? I have not used this scanner yet, so I don't know if they give the option at the beginning. On my Autel for example, When I plug in, I can select OBD2 or select Ford or GM and then scan for the VIN. Sometimes just using the OBD2 side is more generic, and you might see the module. It is a bit odd everything on the module seems to be working, but we dont know how this entire system works. On a recent Chevy the BCM failed, and I found that the rest of the modules in the vehicle will use the last known good data from the BCM to keep the vehicle operating. I have to look into the A/C module some more. I'll post the diagrams for getting to the back of the AC module when we need it. But check one thing, go into the PCM live data with the vehicle running and check for an A/C Pressure Transducer reading. It might just be labeled A/C Pressure, but that sensor is powered and monitored by the PCM not the A/C module, see if there is any reading for that data PID.

That's the correct fuse panel in your first picture, but the joint connector JMB is on the back side just behind that large white connector on the middle right side. It should look like the 3rd diagram one. Also only has red and blue wires coming out of it. We just need to make sure there's no pin fitment issue there. It is also strange; your scan tool seems to pick up the A/C module but then saying not equipped. I see the module in OEM and aftermarket diagrams. What's your VIN number, let's look your vehicle up with that and see if it's different. And your A/C pressure on the Low side of 90 PSI is way too high. Your vehicle is a 1.6 liter, correct?
The JMB is just a joint connector, is probably not plugged into the fuse panel, it's just a plug where the canbus communication wires meet up and go out to other modules.
Also try not to use the A/C with pressures reaching that high, who knows what the High side pressures are reaching.

Okay, I went to a different location to look at wiring diagrams to see if there are any different built models, I came across 4 different builds of this same vehicle. The RB, RBI, RBr, and the HCi. They all have the same size engines, look identical, and list the same year. But there were no listings like this in All Data. I'm not sure if this is country to country type changes or builds, but 1 of them did come with a manual AC system that looks like it doesn't have any communication wiring.
These seem to be different generation vehicles but listed in mostly the same year.

Let's go with what we know for now. In the PCM live data, technically speaking, there should be a data PID with an AC Pressure reading or voltage. According to All Data service info the PCM is responsible for that. If there isn't data on that, there is nothing we can do about that. But the pressures should equal out pretty fast when the vehicle is turned off. If your friend has a set of gauges, can he evacuate the system for you and see how much Freon is present in the system? Most modern A/C machines will measure exactly how much comes out. You have about 100psi lower than it should be on the High side and a little more on the Low side than it should be, but not excessive.
Are you hearing the Air Mix door in the dash moving when you switch it from Cold to Hot, does it get to full heat? I found this system diagnostics to be pretty accurate. It's also for R134A.