I'd start by looking in the FCOM abnormal ops for solution. As there is none available for this kind of problem, I would start using common sense. As always, there are more solutions for a given problem, especially if it is not covered in any of the books in the aircraft... Although returning is a perfectly safe course of action, I would have tried pulling the cb for the wiper (undocumented procedure for an undocumented problem)... DODAR - letter O is quite important.