Three problems related to defogger have been reported for the 1997 Ford F-150. The most recently reported issues are listed below.
Hvac blend door failure, can not heat/air condition or defrost cab.
1997 Ford f150, heater/defrost does not function properly all the time, more often than not blows cold air. In bad weather visabilty is greatly reduced.
Floor heater vents inoperative.