Mk 1 Focus Heater Blower Thermal Fuse

[bernado]

I replaced the blower thermal fuse around a month ago after the fan only worked on max, but now it's gone again.

Before I think about replacing the blower unit itself along with the fuse, is it possible it could have blown due to water ingress?

The reason I'm wondering is both times it blew was when there was rain of almost biblical proportions. The fan itself seemed quite happy when it was working with no unusual noises and was smooth throughout the speed range.

Any thoughts before I replace the fuse again?