The A/C has blown nice and strong since I got this car a couple months ago, and suddenly it stopped. Actually, the air still blows but it's now coming through the defroster and on the floor even though the switch is set to the main vents, and it's not cold at all.

What should I check first? The compressor appears to kick on when I switch on the A/C, but it's still warm and I can't change where the air is coming out.

 

Well sometimes I just need to ask a stupid question in order to find the answer myself. The vacuum check valve had one of the connected hoses disconnected, and popping it back on took care of the issue altogether. Problem solved.