the problem was
Alpine has a butt load of wires on the back of their decks. Even though we trimmed them short before installing, the had to be crammed into the console and then the deck compacted into place. There was apparently an arc going on that caused the wipers to run. I had the tech pull the head unit and disconnect the dimmer wire and reattach. We tested the system and no more wipers. Reinstalled and still no wiper problem. Anything learned? Just not to cram too much wire into a hole too small. WTF.