I just fixed the same problem on mine and the culprit was the relay. It is next to the front fuse box. The relay had worked itself loose. Once I plugged it back in and then taped it together with electrical tape (which I hope will keep it from working itself loose again), the a/c worked like a charm.
The relay was the first thing we checked and it was tight and secure. If the resistor pack went bad the blower motor would not work but it runs fine.