A/C Problems!!!

My '96 Explorer a/c system started acting strange last summer. When you set the temp on the climate control the AC will kick on and blow really hard then it will completely cut off and be replaced with hot air for a few minutes only to have the A/C cut back on full blast! I don't know what to do? Any suggestions? Oh yeah, BTW, the same thing happened this winter, heat then A/C, then heat again. Just really, really frustrating.

Any help is welcomed.

Thanks.