is the compressor coming on when you hit the ac button? you should hear/feel it! could have a bad low or high pressure switch, maybe they didnt plug one of the ac plugs back in........or what im thinking is you might be low on freon! but start with the basics, find out if the compressor is kicking on and get back to me.........i manage a heating/air supply house in memphis and although we dont specialize in cars we do dabble in automotive a/c!
brian