What is the little white box under the dash on a Ford Windstar?

Right behind the radio; there is a white plastic module about the size of a pack of cigarettes

This is the notorious temperature blend door actuator motor

· What the actuator is / does:

· Inside this unit is a circuit board, motor and small plastic round gears. The gears then rotate the actuator, which in turn opens and closes the damper allowing the air to pass through the heater core.
· What happens is some of the little teeth break off creating a gap on the gear wheel. This gap prevents the gears from driving the actuator shaft.
· The dealer may know the unit as a heater damper module. Should cost around $45-$75.

Found else where in WIKI answers; is this it?

See "Related Questions" below for more