On the trip, I encountered a problem with my F/V. It is a flat top version. When I would crank it down, the left side would stay up a bit, and twist the cover so it would not go over the 'wart' on the right side. It would hang up.
Short story, the only thing I could see that might hang up (the seal and all looked fine) was the plunger switch that keep the fan from running when the cover is closed was hitting the crease molded into the cover. I placed a small piece of cardboard on top of the switch, and it closed perfectly, the cardboard overlapping the problem area.
This a.m., I called f/v and explained the problem... he knew exactly what I was talking about... and said the plunger switch was sticking up too far. He is putting a new one in the mail and the change out seems simple enough... should solve the problem..... great customer service.