Complaints are reports from owners of this model year, not findings about any particular vehicle, and a model that sold in large numbers will collect more of them. They are counted here as filed; nothing is inferred from them.
As water leaks in, the wiper may cease to function on the 'intermittent' setting, reducing the driver's visibility and increasing the risk of a crash. Additionally, the water may cause corrosion which, over time, may result in an electrical short, increasing the risk of a fire.
Two 2012 KENWORTH C540s can have entirely different histories, and a recall campaign usually covers a build-date window rather than a whole model year — which a VIN does not encode, so only the door-jamb label settles it. Scanning the VIN adds the decode, the crash tests, the fuel economy and the complaints matched to that exact engine, trim and assembly plant.