What is the cause of the heating/air direction switch not to work? on 1999 Toyota Camry

This is the switch that changes the air to go out the floor vents, the windshield vent (for defogging), etc. Mine stopped working. Won't change from dash vents!! Can't defog my front windshield.

Asked by for the 1999 Toyota Camry
2 answers
Check the resistor (it is located behind the glove box near the blower motor).
poss vac issues or blend door problems