The a/c won't turn on. What could be problem? on 2007 Acura TSX

I changed the fuse but that didn't work. What else should I try?

Asked by for the 2007 Acura TSX
Well, need to check for the a/c line to have enough pressure to 'kick' the compressor on. May just need recharged and they sell the recharge unit at most parts stores.