Cabin air temp sensor location

Hi guys, was wondering where the cabin air temp sensor is located in a 2011 JSW tdi. They're relatively cheap so I want to try replacing it to see if it helps my a/c before I go with the much more likely compressor replacement. Side question- are all the a/c compressors the same across the mk6 vw model ranges or not? I see many options/prices but they all look exactly the same. This is my first car with a/c and it has turned me into a total wuss.

Side side note- I do have a vcds cable and no faults are coming up for the hvac system. But a/c is intermittent/weak.

You most likely need an RCV. Very common. Do a search here. There is even a TSB about it.

Your cabin sensor is not the problem, and you can check to see its reported value if you like, in the Climate's data.

Also make sure BOTH your cooling fans run.

Yeah I've read about the rcv, would a bad one cause the compressor to make noise all by itself? Cooling fans running good.

No, I have never experienced any noises. Of course, an OVERcharged system could make some strange noises, which is unfortunately quite common as lots of DIYrs tend to go after a "low charge" as being the solution to all poor cooling complaints, when it rarely is. But the stores love selling those silly little cans.

So I got an ac pressure gauge and did as instructed- was so hoping that the system was under-charged, but it read as over-charged, so no easy fix for me. The compressor does sound pretty awful, so I'm leaning towards replacing that. Or maybe it just needs some refrigerant let out? Would love to not have to take anything apart(I know, that's silly).
Cabin temp sensor reads correctly btw

You really should let someone who has the equipment and knows what they are doing look at your car.

The only way to know, for sure, 100%, that the system has the correct charge is with a machine that can recover what is in there, pull the system to a vacuum, then recharge it with good accuracy. The modern A/C systems are very sensitive to the charge amount.

As I have already stated : RCVs are VERY common. It is also VERY common for people who do not know any better to go after a low charge as being the only cause of poor cooling, and then overcharge the system, creating even more problems.

If I brought your car into the shop, I would evac and recharge the system so I was sure the proper amount was in it, then run it and check to see the pressure value in the HVAC controller's data, and go from there.

Fair enough, I wasn't going to fiddle with anything until the system was evac'd and checked out by a pro. And then probably still not fiddle with it.

So, took the car to a shop and they used their machine to correctly charge the system. Ac worked fine for a bit then went back to its old ways. Ran the car back at the house, and ac started working again at first, then not. I noticed the cooling fans running at first (ac running cold), then they stopped spinning (no more cold). Could it be as simple as a cooling fan relay, or is this a symptom of the faulty rcv causing miscommunication between the compressor and the fan?

It sounds like the RCV, but you'd need to watch the compressor load and refrigerant pressure values in the Climate module. It is a brutally simple setup. A duty cycled solenoid (the RCV) works to control the compressor's stroke. More stroke, more pressure, more potential pressure DROP at the expansion valve, and that is where the magic happens as the pressure drop immediately after the expansion valve is where the evaporator is, and that is the part that gets cold. When the pressure is high, the fans come on (normal). If it gets really high, the fans speed up (hot day, perhaps not moving much).

When the RCVs flake out, they simply cannot control the pressure and can go all over the place. You could also certainly have an issue with the fans, but that is less likely. Those fans are variable speed through the same circuits (duty cycled), so it isn't like they could work on LOW but not on HIGH like the older cars. They either work or they don't.