Could be, but I dont think your year has a heater control valve.
Best thing to do is get the vehicle hot and feel the heater core hoses, both hot? Cold? Warm?
November, 20, 2010 AT 6:09 AM
There is a big problem with broken blend doors in f150s, and a number of other Fords. In order to repair the problem you must pull the dash and remove the plenum box. Alternatively there are some DIY fixes that have instructions for removing the glovebox and making an incision in the plenum box to replace the blend door.