One problem related to defogger has been reported for the 1999 Ford F-150. The most recently reported issues are listed below.
The contact owns a 1999 Ford F-150. The contact stated that both the air conditioner and the heater were inoperable. The contact was also unable to use the defroster system. The vehicle was taken to an independent mechanic where they advised him that the flapper that was inside the heater blower failed and needed to be replaced. The vehicle was not repaired. The manufacturer was contacted and offered no assistance. The failure mileage was approximately 136,000. The current mileage was approximately 146,000. The VIN was unavailable.