Volkswagen Repair: 2003 GLS TDI A/C Not working, thermal expansion valve, compressor clutch

Question
I turned on the A/C today and it is not working.  I don't remember exactly when the last time was that i used it but it wasn't more than a couple of weeks ago and it seemed to be working just fine then.  today was only about 75 or 80F outside so not a scorcher but the temp of the air coming out of the vents never changed, just the same temp as outside.  I have a scan tool so i checked the fault codes with that but nothing came up about the a/c.  if the a/c is low on refrigerant would there be a fault code?  Also, when i press the a/c button i can hear the compressor clutch engage.  it runs for a bit and then disengages.  Any ideas?  Thanks

Answer
Hi Sean;
The A/C system is probably just low on refrigerant.  When you have it recharged, ask to have some dye injected into the system with the fresh recharge.  If it is seeping out of a fitting, or a hole of some kind, it will be easily detectable, should you need to recharge it again in a short time.  The compressor turns on because there is just enough refrigerant to close the low pressure switch.  The compressor stops because the low pressure switch can't stay closed once the refrigerant moves into the compressor, and on to the thermal expansion valve.