Good call on shutting off the fan in the carwash. Even if the filter wasn't wet when you checked it, there would still have been a significant amount of moisture being drawn through it during the car wash process. Do you have extra wide car washes in your area? Owner's guide says Raptor is too wide for car washes, and from what I've seen I'm inclined to believe it. I wash my truck at home, but it would certainly be nice to have the option of a drive-thru car wash in the winter.