Do you see water under you car, specially after a hot day. If you don't, that may be a clue that is NOT draining properly. If it is your original evaporator...chances are
However, you can get to the drain tubes either from the bottom with a long plastic probe (be careful, the drain tubes are very fragil) or remove the console and you will see them on each side of the radio (approx. location). Is your carpet wet at front?