So i cant seem to get the refrigerator water to work, The fridge is a nice one and only 5 years old. It's my girlfriends and i have tried everything i could think of, and first off, yes the water supply is on

. I have used my compressor to blow the line out in case of some sort of blockage, and have even used my shopvac to suck the system and prime it so to speak. When you try to get water maybe an ounce or two will come out, then nothing. What would be the cause of this?