I FRIGGIN DID IT!!!! Goodbye 4 years of Texas summer heat with a window for A/C! Hello icey frost pouring from my vents!
So, to summarize what has gotten me here:
Looked back over all of my findings so far. Figured that at this point, there were only two things that could have failed. 1) The solenoid. I saw a video where high pressure on low side, and cooling slowly dying off are tip offs to this one. 2) The compressor. Less likely, seeing as to there were no fault codes found for the a/c system. So I poked around some more, and found that Amazon had the solenoid for ~$20. I figured it would not be too difficult to replace.
Set aside a few hours, and got to work. Had the system evacuated, and jacked it up. Removed the c-clip holding it in and realized mistake #1. Fans are in the way. Removed the fans, and popped the solenoid back in. I figured I need to replace the fans anyway, so I better figure out how to do it. Had my buddy assist with the refill, to make sure the weight was right. Used up the rest of the can I started last time, 150g in. It did not seem to fill too quick with the car off, but I did not want to run it dry. Cracked the second can and started the engine up. Started pulling off of the second bottle. Watched the gauges and the high side pressure started creeping up. Checked the vents, and sure enough, icey cold. I'm not gonna lie, I am a grown ass man. But I screamed like a newborn baby with joy. Finally, no more sweating for 45 minutes home every day. Thank you all for the guidance and patience, I greatly appreciate every minute you guys spent walking me through things.
Moral of the story: If you have no cool air, check your scan log. If no codes, check pressures. If you have even pressures on both sides, and the low side is higher than what it should be, spend the $20 to get a new solenoid and try it out. It's super simple and could save you quite a few bucks. Shop quoted me $1200 for a new compressor.
First off, I know it's been awhile, but belated congrats for fixing your ac problem! I wanted to thank you (and everyone else) for all this effort and info! I too have a 2007 GTI and been without ac for almost 3 years, thought I'd share the gist..
I remember when it cut out, it was gradually getting hotter until nothing (clue perhaps). "The clutch of the old compressor had melted and stuck open.. and there's some kind of leak coming from the compressor I think" was Goodyear's diagnosis. $1,750 for compressor, dryer, and supposedly a new relay. I kindly turned them down.
I'm not the most knowledgeable person with all this, just a gearhead that can navigate his way around a motor. Just a couple weeks ago I installed a new compressor, tx valve, condenser, dryer and ac pressure switch. I also had the system evacuated (obviously), leak tested prior to any work at a different shop (passed test), and returned to the shop to get recharged (failed 2nd test after parts installed).
The technician said the system is fully charged and has integrity (no leaks). All the seals were redone by the shop as I had some trouble (it's really a two man job when you disconnect that radiator support) with the condenser connect.
Yet after all that the compressor wouldn't engage. My larger fan turns on but hasn't gotten loud like a jet engine, its rather quiet. I've checked the fan connect, seems ok. Haven't seen the condenser fan run though.
I'm waiting for obd11 to arrive in a few days to pull all that fantastic info about the ac system.
I'm wondering if it's just some code I can clear and problem solved.
I'm gonna attach some gauges today at a friend's house just to see what the actual pressure level is high and low. I didn't get that info in detail at the auto shop (how much refrigerant they added), but I gave them the figures (525g+25, and added 4.7oz PAG 46 oil as compressor didn't come with oil in it).
I've yet to find any relay for the ac system, just fuse locations (two 40amp and one 10a by the door fuse box, one 20a fuse location under the hood), apparently not used in our model. It's seems the condenser fan may somehow determine whether the compressor engages, therefore the FCM (fan control module) is possibly pertinent to the ac system providing cold air, or so I've read and been told by a tech.
Since these compressors run constantly, that too points to that solenoid being the culprit. It's frustrating if the new compressor I installed had a faulty pressure solenoid (not the ac pressure switch).
I am curious about one part of your ac fixing adventure.. did you by chance determine if it was the new fan (some failure of the FCM perhaps), the pressure solenoid that's part of the compressor, or both. Id like to test if the fan really is that important, I have to decide if I want to evac the system all over again to install that solenoid, or go with a new fan. FCM alone $85 on ECS website, whole fan a bit more $150 maybe. Since I've replaced virtually everything else, except evaporator (a massive pita), it's down to these two possibilities. Your situation has helped me to wrap my head around the issue a bit better. Well see what happens.