That pulse control board is an item that commonly fails. From your description, its possible that the combo signal /wiper / cruise switch could be it. When my board went bad it was just the delay that was affected, but your situation may require more detective work because it sounds like the whole system loses power momentarily. I'd be curious what they did at the shop that made it go away. Its possible they re-did some solder joints on the board and now they came back loose. The aftermarket replacements are re-designed with a thicker board. But the location of the component is such that moist air can kinda get to it, so theres no wonder they go bad so often.
