Don't see that as the problem but could be - however under the passenger side is the inlet for the fan - this has a shaped plastic surround that connects to the plastic that runs under the windscreen wipers, I have seen a few where this has split off and moved allowing water to run down the screen and into the fan intake. Worth a look maybe?
They should be a reasonably tight fit though - only clipped in place with 3 10mm bolts (IIRC) to hold them down - the bolts are under little rectangular covers that just pop off - to take the drivers side off you need to remove the wipers.