Windshield Wipers Stopped Working

My windshield wipers will cut off in the middle of wiping my window, for about a minute, then come back on, for about thirty seconds. They are not doing it consistently either. They will work sometimes for a little then just stop for any given time, then come right back on as if nothing was wrong. If I turn them off they continue to wipe/turn off/wipe, until they finally turn off. I have already taken my truck in to Nissan and they "supposedly" changed out the switch. That was about two years ago. I do not understand why this is happening. Please help!