Blower Motor Switch
WARNING: This page is about a different car, the 2005 Mercury Sable and 2005 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.
The blower motor switch (19986) is separately serviceable from the integrated control panel (ICP) (18C858), and controls blower motor speed by adding or by passing resistors in the heater blower motor switch resistor (19A706).