A/C question

06 Jetta TDI, put a new A/C compressor on. Pulled vacuum, well went to start adding the refrigerant and compressor never kicked on. Did notice that when the A/C button is one the accessory fan isnt on. Question is can that cause the compressor not to come on. I've read where some say it can an some say it won't. When car is up to temp both fans do come on. Haven't had a chance to run any diagnostic yet. Before when it worked it would take a while for the compressor to come on, then after this winter wouldn't come on at all.

Thanks in advance for any help.

Do some search in the forums. The mkv didn't have a fan clutch, instead it has a control valve. Fan should come on when the ac is on too.

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Did you ever get the refrigerant added? I don't think it will come on until there is some refrigerant in the system.

I did, would say 3/4 of a can in

So, the way the ac works on the mkv Jetta is different from many other vehicles, which often causes confusion and difficulty.
Most cars use a compressor which has a pulley that is constantly driven by the serpentine belt. Then when you turn on the ac, it will engage a clutch that then drives the compressor. The mkv uses a compressor that is constantly driven, and it has a control valve which controls the pressure and flow of the freon. If I remember right, one terminal is battery positive and the other one is a varying duty cycle dependant on how much flow is needed.
That valve can be quite problematic and many people will diagnose it that it has a bad compressor. But polar air has a new control valve which you can get which could be your problem. Do a search in this forum, there's a very helpful troubleshooting guide.

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A5 Air Conditioning thread

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Thanks for the info

I just replaced the RCV for the second time in one of my 06 Jettas. I had replaced it about 75,000 miles ago. The system is back up and working perfectly again in the 95° weather we had today.