If yoou have access to a "Food Saver", put the control
head in one of the vacume cannisters and pull a good vacume on it. The moisture will "boil off" quickly and you may avoid
corrosion on the board. One thing I don't understand, however, is how the control
head might have been breached. We have essentially the same unit at our
helm station and that has endured virtually any
weather we've thrown at it without a flinch.
In any case, good luck...