[OAC_Sparky]

When the recirc is working properly and the AC is on, the AC heat exchanger not only acts as a cooler, it dries the air as well as the water condenses on the coil. That is why when you run the defroster, the AC runs to dry the air.

When the recirc is on, it stops the outside air from coming in, and pulls air from the cabin. This aids in cooling the cabin air faster. However, if you don't have the AC on, you have nothing to pull the moisture the passengers are breathing out from the air. This will cause condensation on the inside of the window as warm moist air hits a cooler windshield. It's also not a good idea to leave it in the closed position as it tends to encourace mold growth in the heating system.

To be honest, I haven't looked to see if the recirc is electrically or vacuum drive (Ford has both systems). Regardless, I doubt very much there would be a seperate fuse just for that. Have you done anything under your dash lately like put in a new radio, etc?