Air Conditioner not Working

Hey
Seeing as it is the first few hot days of summer here in NYC my air conditioner decided to quit. I will say that the car sat for about a month without being started or moved and I had to use my portable battery jump starter. The AC worked yesterday but is not working today. I am going to have the battery tested and if necessary replaced next week. Any ideas on what would cause the AC to fail?
Thanks

2005.5 VW Jetta TDI

Does the fan run? Have you checked with the VCDS?

redbarron55 said:

Does the fan run? Have you checked with the VCDS?

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When I turn it on it blows room temp air, the heat works. Sorry, I don't know what the VCDS is.

Here:

https://www.ross-tech.com/

It is the definitive tool for VW's.

Lightflyer1 said:

Here:

https://www.ross-tech.com/

It is the definitive tool for VW's.

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Ok, thanks. Not sure if I would know how to use that. I will keep looking .

Plenty of people here to help you. Keep looking if you want but you won't find anything better than this tool. One or two service calls would pay for it.

Lightflyer1 said:

Plenty of people here to help you. Keep looking if you want but you won't find anything better than this tool. One or two service calls would pay for it.

Click to expand...

I checked out the website and it only works on PC's. Everything I have is MAC so looks like I'm sol. Hopefully I will get some suggestions here, or I will have to take it to the shop.
Thanks

Turn on the AC and look under the hood to see if the radiator fans are turning. If they don't, it might be the RCV valve in the AC compressor. If that is the case, an error will not be triggered in VCDS.

Some here have run it on a MAC using VM or some such (I am not MAC knowledgeable).

There are Youtube Vids, google that can help you understand how AC works, what components there are, and how to do generic trouble shooting.

BLOWN FUSE would be the best news, easy to fix. As suggested does recalculation fan work? Do you hear the clutch kick in (if it is a clutched AC compressor). The clutch can be jumped to eliminate the AC switch circuit. Id you have a newer variable output compressor like my 2010 it is different.

I don't know 2005.5 system. I assume it is the older most common design of AC clutch compressor (verses the later VW's that have variable output through a change in piston stroke). The older designes were 100% on and then went 100% off.... They cycled to maintain Temp. The newer ones run at a level to maintain temperature.

What could have gone wrong... ANYTHING including the AC switch in the dash to a blown compressor or even massive loss of freon.... there are ways to check everything. Is the belt still there? There are so many basic checks, but if you don't have the wherewithal bring it to a professional.... pay your money.... or sweat...

VCDS will not tell you much if anything about the AC in a 2005.5.

relumalutan said:

Turn on the AC and look under the hood to see if the radiator fans are turning. If they don't, it might be the RCV valve in the AC compressor. If that is the case, an error will not be triggered in VCDS.

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I saw that the fans were turning and did some more research. I wound up recharging the AC system and that seems to have done the trick.
As always thanks for the help.

Did you evacuate and recharge with the correct amount of freon or just add some?