Adding Freon to 1995 UrS6

[Jay M]

Hello all, My 1995 S6 is blowing warm air when AC is on full blast. I hear the compressor working but air coming out of vents is not cold at all. I suspect the system needs a topping off of R134A freon. Although I have never charged the Audi S6 AC system with freon before I know on my other cars it is not a difficult task. The problem I have with the S6 is I can't determine where exactly the Low side port is located to attach my can of R134a. I did research and that indicates the S6 system holds about 1.7 pounds of Freon and should be filled to about 50 PSI on the low side when the ambient outside temp is 90 degrees. I looked and found an obvious and easily accessible port on the passenger side condensing unit located in front of the radiator but that seems too good to be true. I also found another port tucked away on driver side behind the radiaror. Can anybody tell me with 100% certainty where the low side port is located so I can attempt to recharge my AC system without blowing up the can of R134A?  JM